ASoC: Allow more routing features for tlv320aic3x

This patch enables more routing functions for tlv320aic3x codecs.
It is now possible to

 - control the volume of the PGA bypass path for the HPL, HPR, HPLCOM
   and HPRCOM outputs individually
 - route right line1 input to the left ADC channel
 - route left line1 input to the right ADC channel
 - route right mic3 input to left DAC channel
 - route left mic3 input to right DAC channel
 - route left line1 input to right line1 output
 - route right line1 input to left line1 output

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>