ARM: 8072/1: time: Make use of arm_get_current_stackframe

Make use of the arm_get_current_stackframe api so that
the frame pointer is correctly referenced in THUMB2 mode

Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>