arm64: Provide read/write fault information in compat signal handlers

For AArch32, bit 11 (WnR) of the FSR/ESR register is set when the fault
was caused by a write access and applications like Qemu rely on such
information being provided in sigcontext. This patch introduces the
ESR_EL1 tracking for the arm64 kernel faults and sets bit 11 accordingly
in compat sigcontext.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-commit: 9141300a5884b57cea6d32c4e3fd16a337cfc99a
[joonwoop@codeaurora.org: fixed trivial merge conflict.]
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>