target/sh4: Let get_physical_address() use MMUAccessType access_type

superh_cpu_tlb_fill() already provides a access_type variable of
type MMUAccessType, and it is passed along, but casted as integer
and renamed 'rw'.
Simply replace 'int rw' by 'MMUAccessType access_type'.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210127232151.3523581-5-f4bug@amsat.org>