radeonsi/vce: Fix bitstream buffer size

On old VCE this was being rejected by kernel because the size here
was the buffer size, but the bitstream buffer address includes the
offset.

Fixes: 901aafb030f ("radeonsi/vce: Support raw packed headers")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/13128
Reviewed-by: Ruijing Dong <ruijing.dong@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34894>
1 file changed