lavu/hash: Fix adler32 calculation

Adler must be initialized with a non zero value.

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
lavu/hash: Fix CRC32 calculation

Initialize it with UINT32_MAX and xor the result with UINT32_MAX
as well.

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>