drm/xe/uapi: Remove useless max_page_size

The min_page_size is useful information to ensure alignment and it is
an API actually in use. However max_page_size doesn't bring any useful
information to the userspace hence being not used at all.

So, let's remove and only bring it back if that ever gets used.

Suggested-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Francois Dugast <francois.dugast@intel.com>