Merge Linux 4.4.255 kernel

Changes in 4.4.255: (29 commits)
        ACPI: sysfs: Prefer "compatible" modalias
        wext: fix NULL-ptr-dereference with cfg80211's lack of commit()
        net: usb: qmi_wwan: added support for Thales Cinterion PLSx3 modem family
        KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[]
        mt7601u: fix kernel crash unplugging the device
        mt7601u: fix rx buffer refcounting
        y2038: futex: Move compat implementation into futex.c
        futex: Move futex exit handling into futex code
        futex: Replace PF_EXITPIDONE with a state
        exit/exec: Seperate mm_release()
        futex: Split futex_mm_release() for exit/exec
        futex: Set task::futex_state to DEAD right after handling futex exit
        futex: Mark the begin of futex exit explicitly
        futex: Sanitize exit state handling
        futex: Provide state handling for exec() as well
        futex: Add mutex around futex exit
        futex: Provide distinct return value when owner is exiting
        futex: Prevent exit livelock
        ARM: imx: build suspend-imx6.S with arm instruction set
        netfilter: nft_dynset: add timeout extension to template
        xfrm: Fix oops in xfrm_replay_advance_bmp
        RDMA/cxgb4: Fix the reported max_recv_sge value
        mac80211: pause TX while changing interface type
        can: dev: prevent potential information leak in can_fill_info()
        iommu/vt-d: Gracefully handle DMAR units with no supported address widths
        iommu/vt-d: Don't dereference iommu_device if IOMMU_API is not built
        NFC: fix resource leak when target index is invalid
        NFC: fix possible resource leak
        Linux 4.4.255

Conflicts:
	kernel/exit.c