libbrasero-media: Fix memset() warning

libbrasero-media/scsi-read-track-information.c: In function ‘brasero_read_track_info’:
libbrasero-media/scsi-read-track-information.c:116:33: warning: argument to ‘sizeof’ in ‘memset’ call is the same pointer type ‘BraseroScsiTrackInfo *’ {aka ‘struct _BraseroScsiTrackInfo *’} as the destination; expected ‘BraseroScsiTrackInfo’ {aka ‘struct _BraseroScsiTrackInfo’} or an explicit length [-Wsizeof-pointer-memaccess]
  116 |         memset (&hdr, 0, sizeof (info));
      |                                 ^