target/mips/mxu: Add D32SARL D32SARW instructions These instructions are dual 32-bit arithmetic shift right and pack LSBs to 2x 16-bit into a MXU register. The difference is the shift amount source: immediate or GP reg. Signed-off-by: Siarhei Volkau <lis8215@gmail.com> Message-Id: <20230608104222.1520143-25-lis8215@gmail.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>