target/mips/mxu: Add Q8MAC Q8MACSU instructions

These instructions do parallel quad 8-bit multiply and accumulate.
They are close to existing Q8MUL Q8MULSU so the generation
function modified to support all of them.
Also the patch fixes decoding of Q8MULSU according to tests on
hardware.

Signed-off-by: Siarhei Volkau <lis8215@gmail.com>
Message-Id: <20230608104222.1520143-30-lis8215@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
1 file changed