mcrf broke when we changed analyse_instr() to not modify the register
state. The instruction writes to the CR, so we need to store the result
in op->ccval, not op->val.

Fixes: 3cdfcbfd ("powerpc: Change analyse_instr so it doesn't modify *regs")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>