radesonsi/vcn: update vcn4 tile processing logic

Vcn4 tile number calculation doesn't consider
some input case, which could result in output
bitstream corruption, this fixed the issue.

Not using the number_of_tiles directly but from
calculation. Also change to re-use some macros
from local vcn_5_0.c to ac_vcn_enc.h header file.

Updated vcn4 spec_misc_av1 ip package.

Reviewed-by: Boyuan Zhang <Boyuan.Zhang@amd.com>
Signed-off-by: Ruijing Dong <ruijing.dong@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29556>