m7-common: add HTC TFA9887 config files

Change-Id: I2d72287846ced8fda55609151ee2ac3d484cce7c
m7-common: libaudioamp: split amp functionality into amp files

Change-Id: Idd5c0e73a4d49b6f8ba227bd1de2e33f92500960
m7-common: tfa9887: set up DSP mode

Change-Id: Ie51c5a27409c76b9394a85ce1dc9cfe18679a996