bktr: add missing #include for av_gettime()

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavdevice/bktr.c

@@ -28,6 +28,7 @@
 #include "libavutil/log.h"
 #include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
+#include "libavutil/time.h"
 #if HAVE_DEV_BKTR_IOCTL_METEOR_H && HAVE_DEV_BKTR_IOCTL_BT848_H
 # include <dev/bktr/ioctl_meteor.h>
 # include <dev/bktr/ioctl_bt848.h>