drm/i915: Use memmove() for punching the hole into infoframes

Replace the hand rolled memmove() with the real thing.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180920185145.1912-9-ville.syrjala@linux.intel.comReviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_hdmi.c

@@ -457,9 +457,7 @@ static void intel_write_infoframe(struct drm_encoder *encoder,
 		return;
 
 	/* Insert the 'hole' (see big comment above) at position 3 */
-	buffer[0] = buffer[1];
-	buffer[1] = buffer[2];
-	buffer[2] = buffer[3];
+	memmove(&buffer[0], &buffer[1], 3);
 	buffer[3] = 0;
 	len++;