accel/tcg: Split out tb_flush__exclusive_or_serial

Expose a routine to be called when no cpus are running.
Simplify the do_tb_flush run_on_cpu callback, because
that is explicitly called with start_exclusive; there
is no need for the mmap_lock as well.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2 files changed