drm/xe/migrate: Fix alignment check

The check would fail if the address is unaligned, but not when
accounting the offset. Instead of `buf | offset` it should have
been `buf + offset`. To make it more readable and also drop the
uintptr_t, just use the IS_ALIGNED() macro.

Fixes: 270172f ("drm/xe: Update xe_ttm_access_memory to use GPU for non-visible access")
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://lore.kernel.org/r/20250710-migrate-aligned-v1-1-44003ef3c078@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
(cherry picked from commit 81e139d)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Author: Lucas De Marchi

drivers/gpu/drm/xe/xe_migrate.c

@@ -1817,8 +1817,8 @@ int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo *bo,
 	xe_bo_assert_held(bo);
 
 	/* Use bounce buffer for small access and unaligned access */
-	if (len & XE_CACHELINE_MASK ||
-	    ((uintptr_t)buf | offset) & XE_CACHELINE_MASK) {
+	if (!IS_ALIGNED(len, XE_CACHELINE_BYTES) ||
+	    !IS_ALIGNED((unsigned long)buf + offset, XE_CACHELINE_BYTES)) {
 		int buf_offset = 0;
 
 		/*