ARM: 8075/1: oprofile: Use of arm_get_current_stackframe

Use the newly introduced API so that FP is correctly referenced from
either R7/R11 based on whether we are running in THUMB2 mode or not.

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