Like Skylake, we can support  4 channel for DMIC, so add
hw_params and constraints in the bxt-rt298 machine

While at it, also add codec1 pipe for speaker playback.
Signed-off-by: Senthilnathan Veppur <senthilnathanx.veppur@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>