04d2540c added intreadwrite.h to avienc.c, although there was (and is)
no need to do so. The inclusion seems to be a mistake as this commit
added a AV_WL32 to avidec.c.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>