gdbstub: specialise target_memory_rw_debug

The two implementations are different enough to encourage having a
specialisation and we can move some of the softmmu only stuff out of
gdbstub.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230302190846.2593720-16-alex.bennee@linaro.org>
Message-Id: <20230303025805.625589-16-richard.henderson@linaro.org>
4 files changed