winsys: clamp up the alignment to gart_page_size
Zero alignment buffers is a valid alignment and is used for the cases when there is no special alignment enforced due to hardware requirement.
Adding this check will not return NULL for a valid allocation. Screenshot app allocates such buffers with zero alignment which returns NULL and failed to capture.
Signed-off-by: Sunil Khatri sunil.khatri@amd.com