arm64: Unmask asynchronous aborts when in kernel mode

The asynchronous aborts are generally fatal for the kernel but they can
be masked via the pstate A bit. If a system error happens while in
kernel mode, it won't be visible until returning to user space. This
patch enables this kind of abort early to help identifying the cause.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: b3bf6aa7e79117419f7eddccf0b7af4382d823c3
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>