Restartable sequences: ARM 32 architecture support

Restartable sequences: ARM 32 architecture support

Call the rseq_handle_notify_resume() function on return to
userspace if TIF_NOTIFY_RESUME thread flag is set.

Increment the event counter and perform fixup on the pre-signal frame
when a signal is delivered on top of a restartable sequence critical
section.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
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