target/microblaze: Remove last of old decoder

All instructions have been convered.  Issue sigill if decodetree
does not match.  Remove argument decode from DisasContext.
Remove microblaze-decode.h.

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