media: radio-wl1273: fix a parameter name at kernel-doc macro

Solve those warnings:
	drivers/media/radio/radio-wl1273.c:1337: warning: No description found for parameter 'radio'
	drivers/media/radio/radio-wl1273.c:1337: warning: Excess function parameter 'core' description in 'wl1273_fm_set_tx_power'

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