tcg: Add tcg_get_insn_start_param

MicroBlaze will shortly need to update a parameter in place.
Add an interface to read to match that for write.

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>
1 file changed