arm64: compat: Add CNTVCT trap handler

Since people seem to make a point in breaking the userspace visible
counter, we have no choice but to trap the access. We already do this
for 64bit userspace, but this is lacking for compat. Let's provide
the required handler.

Change-Id: I5fb1fa1f613b9524b6af800b1ea7bf512929af85
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: 50de013d22e4e112d7b0778a0e7d032f16c46778
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>