22 to see whether
the instruction actually is a write back instruction or not. I think
it's enough to check whether Rn != PC,  because:
- it's looks cheaper than the alternative
- to my understaning it's not permitted to update the PC with a write
back instruction, so we don't lose any ability to emulate legal
instructions.
- in case of writing back for non write back instructions where Rn != PC, it doesn't matter because the values are the same.

Regarding the second point above, it would possibly be prudent to add
some checking to prep_emulate_ldr_str(), so that instructions with
both write back and Rn == PC would be rejected.

Signed-off-by: Viktor Rosendahl <viktor.rosendahl@nokia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
k