mlpdec: move rematrix_channels code to output_data()

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: James Almer <jamrial@gmail.com>
x86/mlpdec: add ff_mlp_rematrix_channel_{sse4,avx2}

2x to 2.5x faster than the C version.

Reviewed-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: James Almer <jamrial@gmail.com>
avcodec/utils: Add case for jv to avcodec_align_dimensions2()

Fixes out of array accesses
Fixes: asan_heap-oob_12304aa_8_asan_heap-oob_4da4f3_300_intro.jv

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>