Move the update_avsync_before_frame() call further down. Moving it
closer to where the time_frame value is used (and which the function
updates) should make the code more readable. With this change, there's
no need anymore to reset the time_frame value on the video reconfig
path.
Move the update_avsync_after_frame() up. Now no meaningful amount of
time passes since the previous get_relative_time() call anymore, and the
second one can be removed.