target/microblaze: Force rtid, rted, rtbd to exit

These return-from-exception type instructions have modified
MSR to re-enable various forms of interrupt.  Force a return
to the main loop.

Consolidate the cleanup of tb_flags into mb_tr_translate_insn.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed