target/mips: Let cpu_mips_translate_address() take MMUAccessType arg

The single caller, do_translate_address(), passes MMUAccessType
to cpu_mips_translate_address(). Let the prototype use it as
argument, as it is stricter than an integer.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20210128144125.3696119-10-f4bug@amsat.org>