drm/i915: Fix user ptr check size in eb_relocate_vma()

Fix the sizeof(ptr) vs. sizeof(*ptr) typo.

Fixes: 2889caa9 ("drm/i915: Eliminate lots of iterations over the execobjects array")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170714151242.517-2-imre.deak@intel.com

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -1459,7 +1459,7 @@ static int eb_relocate_vma(struct i915_execbuffer *eb, struct i915_vma *vma)
 	 * to read. However, if the array is not writable the user loses
 	 * the updated relocation values.
 	 */
-	if (unlikely(!access_ok(VERIFY_READ, urelocs, remain*sizeof(urelocs))))
+	if (unlikely(!access_ok(VERIFY_READ, urelocs, remain*sizeof(*urelocs))))
 		return -EFAULT;
 
 	do {