Vivid update to v3.19.8-ckt20 stable release

SRU Justification

    Impact:
       The upstream process for stable tree updates is quite similar
       in scope to the Ubuntu SRU process, e.g., each patch has to
       demonstrably fix a bug, and each patch is vetted by upstream
       by originating either directly from a mainline/stable Linux tree or
       a minimally backported form of that patch. The v3.19.8-ckt20 upstream stable
       patch set is now available. It should be included in the Ubuntu
       kernel as well.

       git://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt

    TEST CASE: TBD

       The following patches from the v3.19.8-ckt20 stable release shall be applied:

Linux 3.19.8-ckt20
atl2: Disable unimplemented scatter/gather feature
net: ethernet: davinci_emac: Fix platform_data overwrite
net: ethernet: davinci_emac: Fix Unbalanced pm_runtime_enable
Input: pmic8xxx-pwrkey - fix algorithm for converting trigger delay
net: bcmgenet: device stats are unsigned long
s390/spinlock: avoid yield to non existent cpu
pinctrl: single: Fix pcs_parse_bits_in_pinctrl_entry to use __ffs than ffs
bpf/verifier: reject invalid LD_ABS | BPF_DW instruction
net: sched: do not requeue a NULL skb
packet: fix heap info leak in PACKET_DIAG_MCLIST sock_diag interface
s390/scm_blk: fix deadlock for requests != REQ_TYPE_FS
x86 EDAC, sb_edac.c: Take account of channel hashing when needed
x86 EDAC, sb_edac.c: Repair damage introduced when "fixing" channel address
x86/mm/xen: Suppress hugetlbfs in PV guests
mm: hugetlb: allow hugepages_supported to be architecture specific
drm: Loongson-3 doesn't fully support wc memory
drm/radeon: forbid mapping of userptr bo through radeon device file
drm/dp/mst: Validate port in drm_dp_payload_send_msg()
ALSA: pcxhr: Fix missing mutex unlock
futex: Acknowledge a new waiter in counter before plist
futex: Handle unlock_pi race gracefully
drm/radeon: add a quirk for a XFX R9 270X
powerpc: Update cpu_user_features2 in scan_features()
powerpc: scan_features() updates incorrect bits for REAL_LE
ALSA: hda/realtek - Add ALC3234 headset mode for Optiplex 9020m
video: ARM CLCD: runtime check for Versatile
crypto: ccp - Prevent information leakage on export
crypto: sha1-mb - use corrcet pointer while completing jobs
usb: hcd: out of bounds access in for_each_companion
USB: uas: Add a new NO_REPORT_LUNS quirk
xhci: fix 10 second timeout on removal of PCI hotpluggable xhci controllers
usb: xhci: fix xhci locking up during hcd remove
usb: xhci: fix wild pointers in xhci_mem_cleanup
usb: host: xhci: add a new quirk XHCI_NO_64BIT_SUPPORT
xhci: resume USB 3 roothub first
usb: xhci: applying XHCI_PME_STUCK_QUIRK to Intel BXT B0 host
lib: lz4: fixed zram with lz4 on big endian machines
dmaengine: dw: fix master selection
ALSA: hda - Fix regression of monitor_present flag in eld proc file
nl80211: check netlink protocol in socket release notification
ALSA: usb-audio: Skip volume controls triggers hangup on Dell USB Dock
assoc_array: don't call compare_object() on a node
drm/qxl: fix cursor position with non-zero hotspot
ARM: OMAP2+: hwmod: Fix updating of sysconfig register
HID: usbhid: fix inconsistent reset/resume/reset-resume behavior
ipv6: l2tp: fix a potential issue in l2tp_ip6_recv
ipv4: l2tp: fix a potential issue in l2tp_ip_recv
rtnl: fix msg size calculation in if_nlmsg_size()
qmi_wwan: add "D-Link DWM-221 B1" device id
xfrm: Fix crash observed during device unregistration and decryption
bonding: fix bond_get_stats()
qlge: Fix receive packets drop.
farsync: fix off-by-one bug in fst_add_one
macvtap: always pass ethernet header in linear
sh_eth: fix NULL pointer dereference in sh_eth_ring_format()
net: validate variable length ll headers
udp6: fix UDP/IPv6 encap resubmit path
cdc_ncm: toggle altsetting to force reset before setup
qmi_wwan: add Sierra Wireless EM74xx device ID
sctp: lack the check for ports in sctp_v6_cmp_addr
net: qca_spi: clear IFF_TX_SKB_SHARING
net: jme: fix suspend/resume on JMC260
tunnel: Clear IPCB(skb)->opt before dst_link_failure called