res/res_rtp_asterisk: Enable rxjitter calculation for video

It looks like we're not properly calculating jitter values on received
video streams.  This patch enables the code that does jitter calculations
for those streams.

Change-Id: Iaac985808829c8f034db8c57318789c4c8c11392

res/res_rtp_asterisk.c

@@ -5847,6 +5847,7 @@ static struct ast_frame *ast_rtp_read(struct ast_rtp_instance *instance, int rtc
 		/* Video -- samples is # of samples vs. 90000 */
 		if (!rtp->lastividtimestamp)
 			rtp->lastividtimestamp = timestamp;
+		calc_rxstamp(&rtp->f.delivery, rtp, timestamp, mark);
 		ast_set_flag(&rtp->f, AST_FRFLAG_HAS_TIMING_INFO);
 		rtp->f.ts = timestamp / (rtp_get_rate(rtp->f.subclass.format) / 1000);
 		rtp->f.samples = timestamp - rtp->lastividtimestamp;