drm/i915/selftest_migrate: Consider the possible roundup of size

Consider the possible round up happened at obj size alignment to
min_page_size during the obj allocation.
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405150840.29351-7-ramalingam.c@intel.com

drivers/gpu/drm/i915/gt/selftest_migrate.c

@@ -152,6 +152,9 @@ static int clear(struct intel_migrate *migrate,
 	if (IS_ERR(obj))
 		return 0;
 
+	/* Consider the rounded up memory too */
+	sz = obj->base.size;
+
 	for_i915_gem_ww(&ww, err, true) {
 		err = i915_gem_object_lock(obj, &ww);
 		if (err)