av_log() expects its first parameter to be a pointer to a struct whose
first element is a pointer to an AVClass. In what I can only imagine is
a typo, one call to av_log() in the AAX decryption code instead passes
a pointer to an AVSHA struct, which doesn't even contain a pointer as
its first element, much less a pointer to an AVClass. Change the call to
pass the current MOVContext, as surrounding calls do.

The incorrect AVClass was causing mpv to emit the warning "av_log
callback called with bad parameters" when playing an .aax file.
Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>