panfrost: avoid accidental aliasing

We already have a variable call "alignment" here, and aliasing it
breaks things. Whoops, let's rename the variable to page_size to
avoid this.

Fixes: 22985caf3ff ("panfrost: sanity-check alignment")
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Eric R. Smith <eric.smith@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34156>
1 file changed