Xenial update to 4.4.77 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 4.4.77 upstream stable
       patch set is now available. It should be included in the Ubuntu
       kernel as well.

       git://git.kernel.org/

    TEST CASE: TBD

The following patches from the 4.4.77 stable release shall be applied:
* fs: add a VALID_OPEN_FLAGS
* fs: completely ignore unknown open flags
* driver core: platform: fix race condition with driver_override
* bgmac: reset & enable Ethernet core before using it
* mm: fix classzone_idx underflow in shrink_zones()
* tracing/kprobes: Allow to create probe with a module name starting with a
  digit
* usb: dwc3: replace %p with %pK
* USB: serial: cp210x: add ID for CEL EM3588 USB ZigBee stick
* Add USB quirk for HVR-950q to avoid intermittent device resets
* usb: usbip: set buffer pointers to NULL after free
* usb: Fix typo in the definition of Endpoint[out]Request
* mac80211_hwsim: Replace bogus hrtimer clockid
* sysctl: don't print negative flag for proc_douintvec
* sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec
* pinctrl: sh-pfc: r8a7791: Fix SCIF2 pinmux data
* pinctrl: meson: meson8b: fix the NAND DQS pins
* pinctrl: sunxi: Fix SPDIF function name for A83T
* pinctrl: mxs: atomically switch mux and drive strength config
* pinctrl: sh-pfc: Update info pointer after SoC-specific init
* USB: serial: option: add two Longcheer device ids
* USB: serial: qcserial: new Sierra Wireless EM7305 device ID
* gfs2: Fix glock rhashtable rcu bug
* x86/tools: Fix gcc-7 warning in relocs.c
* x86/uaccess: Optimize copy_user_enhanced_fast_string() for short strings
* ath10k: override CE5 config for QCA9377
* KEYS: Fix an error code in request_master_key()
* RDMA/uverbs: Check port number supplied by user verbs cmds
* mqueue: fix a use-after-free in sys_mq_notify()
* tools include: Add a __fallthrough statement
* tools string: Use __fallthrough in perf_atoll()
* tools strfilter: Use __fallthrough
* perf top: Use __fallthrough
* perf intel-pt: Use __fallthrough
* perf thread_map: Correctly size buffer used with dirent->dt_name
* perf scripting perl: Fix compile error with some perl5 versions
* perf tests: Avoid possible truncation with dirent->d_name + snprintf
* perf bench numa: Avoid possible truncation when using snprintf()
* perf tools: Use readdir() instead of deprecated readdir_r()
* perf thread_map: Use readdir() instead of deprecated readdir_r()
* perf script: Use readdir() instead of deprecated readdir_r()
* perf tools: Remove duplicate const qualifier
* perf annotate browser: Fix behaviour of Shift-Tab with nothing focussed
* perf pmu: Fix misleadingly indented assignment (whitespace)
* perf dwarf: Guard !x86_64 definitions under #ifdef else clause
* perf trace: Do not process PERF_RECORD_LOST twice
* perf tests: Remove wrong semicolon in while loop in CQM test
* perf tools: Use readdir() instead of deprecated readdir_r() again
* md: fix incorrect use of lexx_to_cpu in does_sb_need_changing
* md: fix super_offset endianness in super_1_rdev_size_change
* tcp: fix tcp_mark_head_lost to check skb len before fragmenting
* staging: vt6556: vnt_start Fix missing call to vnt_key_init_table.
* staging: comedi: fix clean-up of comedi_class in comedi_init()
* ext4: check return value of kstrtoull correctly in reserved_clusters_store
* x86/mm/pat: Don't report PAT on CPUs that don't support it
* saa7134: fix warm Medion 7134 EEPROM read
* Linux 4.4.77