[media] cx231xx: change usage of I2C_1 to the real i2c port

change almost all instances of I2C_1 to I2C_1_MUX_3

Only these cases are changed to I2C_1_MUX_1:
* All that have dont_use_port_3 set.
* CX231XX_BOARD_HAUPPAUGE_EXETER, old code did explicitly not switch to port3.
* eeprom access for 930C

Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>