V4L/DVB (6977): tda18271: clean up calibration initialization procedures

Always initialize registers during attach.

Perform IR Calibration during init if needed.
Perform RF Calibration during init if needed for C2, only.

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