avcodec/on2avc: Unify initializing quad and pair VLCs

avcodec/on2avc: Unify initializing quad and pair VLCs

Up until now, quad VLCs are initialized with codes of type uint32_t,
pair VLCs with codes of type uint16_t. There were two separate loops in
the decoder's init function for each type of VLC. This commit unifies
this: The type of the codes are now passed in as void * and the actual
size of the codes is obtained from a table. This approach also allows to
use the smallest type for each VLC code table: some quad tables actually
fitted in uint16_t. This allows to remove about 7KB from the binary.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>