zink: clamp max buffer sizes to smallest buffer heap size

the max driver limit for these is irrelevant if there isn't enough memory
to allocate a buffer of that size

KHR-GL46.texture_buffer.texture_buffer_max_size

cc: mesa-stable

fixes #5568

Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13584>
1 file changed