media: dvb_frontend fix kernel_doc markups

There were some troubles there:
	drivers/media/dvb-core/dvb_frontend.c:379: warning: No description found for parameter 'fe'
	drivers/media/dvb-core/dvb_frontend.c:379: warning: No description found for parameter 'check_wrapped'
	drivers/media/dvb-core/dvb_frontend.c:1265: warning: No description found for parameter 'p_out'

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>