arm: Add condition code check to SWP emulator

When emulating a SWP/SWPB instruction, check the condition
code of the instruction and compare it against CPSR status
bits rather than relying on the architecture to only raise
an undefined instruction exception if the condition checks
are passing.

Change-Id: I9707960b091c3a5af20e396e0b6d5ed2aaf935ff
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>