tcg/ppc: Use new registers for LQ destination

tcg/ppc: Use new registers for LQ destination

LQ has a constraint that RTp != RA, else SIGILL.
Therefore, force the destination of INDEX_op_qemu_*_ld128 to be a
new register pair, so that it cannot overlap the input address.

This requires new support in process_op_defs and tcg_reg_alloc_op.

Cc: qemu-stable@nongnu.org
Fixes: 526cd4ec01f ("tcg/ppc: Support 128-bit load/store")
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240102013456.131846-1-richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>