LSA and LDSA opcodes are also available with MIPS release 6.
Introduce the decodetree config files and call the decode()
helpers in the main decode_opc() loop.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20201215225757.764263-24-f4bug@amsat.org>