[ARM] 3533/1: Implement the __raw_(read|write)_can_lock functions on ARM

Patch from Catalin Marinas

Recent patches introduced the write_can_lock() call in the kernel/ptrace.c
file. Implement the __raw_* variants on ARM (SMP) as well.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>