drm/etnaviv: Use 'unsigned' type to count the number of pages

The unpin_user_pages() function takes an 'unsigned long' argument to
store the number of userspace pages, and the struct drm_gem_object::size
is a size_t type. The number of pages can not be negative, hence, use
'unsigned' variable to count the number of pages.

Reviewed-by: Christian Gmeiner <cgmeiner@igalia.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

Author: suijingfeng

drivers/gpu/drm/etnaviv/etnaviv_gem.c

@@ -686,7 +686,7 @@ static void etnaviv_gem_userptr_release(struct etnaviv_gem_object *etnaviv_obj)
 		kfree(etnaviv_obj->sgt);
 	}
 	if (etnaviv_obj->pages) {
-		int npages = etnaviv_obj->base.size >> PAGE_SHIFT;
+		unsigned int npages = etnaviv_obj->base.size >> PAGE_SHIFT;
 
 		unpin_user_pages(etnaviv_obj->pages, npages);
 		kvfree(etnaviv_obj->pages);