gallium/pipe: Align allocation size in `pb_cache_manager_create_buffer`

Some drivers have minimum buffer size or alignment requirements. When a
buffer is created using pb_cache_manager_create_buffer, the cache is
first checked for a compatible buffer to return instead. If the
requested buffer size is less than
(minimum buffer size) / (mgr->size_factor), no buffer in the cache
is _ever_ applicable.
The alignment is used to determine the true allocation size when
evaluating against cached buffers.

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19082>
1 file changed