* commit '1f0c6075':
  4xm: drop pointless assert

Conflicts:
	libavcodec/4xm.c

The added condition is impossible to occur and thus is added to the assert.
The assert is not removed from the default case, as the default case cannot
occur. Thus either it should stay as is or the case as a whole be removed.
For extra safety, to ensure this doesnt change the assert is changed to
av_assert0()
Merged-by: Michael Niedermayer <michaelni@gmx.at>