clocksource: arm_arch_timer: Enable counter access for 32-bit ARM

The only difference between arm and arm64's implementations of
arch_counter_set_user_access is that 32-bit ARM does not enable user
access to the virtual counter.  We want to enable this access for the
32-bit ARM VDSO, so copy the arm64 version to the driver itself, and
remove the arch-specific implementations.

Bug: 18273388
Change-Id: Iddeefaba3c9b9e57344c6b2cef27c766a4bd686b
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Git-commit: 8b8dde00
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[mattw@codeaurora.org: resolved trivial context conflicts]
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>