exec/translator: Pass the locked filepointer to disas_log hook

We have fetched and locked the logfile in translator_loop.
Pass the filepointer down to the disas_log hook so that it
need not be fetched and locked again.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-13-richard.henderson@linaro.org>