dsputil: Split bswap*_buf() off into a separate context
indeo45: use is_indeo4 context flag instead of checking codec ID

Signed-off-by: Kostya Shishkov <kostya.shishkov@gmail.com>
lzo: Handle integer overflow

get_len can overflow for specially crafted payload.

Reported-By: Don A. Baley <donb@securitymouse.com>
CC: libav-stable@libav.org
h264: avoid using uninitialized memory in NEON chroma mc

Adapt commit 982b596ea6640bfe218a31f6c3fc542d9fe61c31 for the arm and
aarch64 NEON asm. 5-10% faster on Cortex-A9.