MN10300: Handle misaligned postinc-with-imm addressing mode correctly

Correctly handle misalignment in MOV instructions with postinc-with-immediate
addressing mode operands.  In these, the immediate value is the increment to
be applied the address register, not the displacement to the address.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>