Use common functions to access TEA575x tuner - remove original read/write
functions and provide new pin manipulation functions instead.

Also convert the original triple implementation to a simple GPIO pin map.

Tested with SF256-PCP and SF64-PCR (added the GPIO pin for MO/ST signal
for them).
SF256-PCS untested (pin for MO/ST signal is a guess).
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>