media: mt2063: fix some kernel-doc warnings

Fix those warnings:
	drivers/media/tuners/mt2063.c:1413: warning: No description found for parameter 'f_ref'
	drivers/media/tuners/mt2063.c:1413: warning: Excess function parameter 'f_Ref' description in 'MT2063_fLO_FractionalTerm'
	drivers/media/tuners/mt2063.c:1476: warning: Excess function parameter 'f_Avoid' description in 'MT2063_CalcLO2Mult'

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