fate: Explicitly specify the rgb555le pixel format for the mss2 rgb555 tests

This fixes these fate tests on big endian.

Signed-off-by: Martin Storsjö <martin@martin.st>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  fate: Explicitly specify the rgb555le pixel format for the mss2 rgb555 tests

See: 34e90b2e6d66c511bea872bcb3a0e34b482b8c17
Merged-by: Michael Niedermayer <michaelni@gmx.at>
avformat/matroskadec: check generic audio deinterleaver sub_packet_size against frame_size

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7f67d052a530_7517_nosound.mkv
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>