[media] Docbook: Fix s_rx_carrier_range parameter description

Warning(.//include/media/rc-core.h:178): No description found for parameter 's_rx_carrier_range'
Warning(.//include/media/rc-core.h:178): Excess struct/union/enum/typedef member 's_rx_carrier' description in 'rc_dev'

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>