V4L/DVB (6958): tda18271: clean up function tda18271_set_analog_params

make set_analog_params function look consistent with set_params function

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>