Revert "m4: remove audioamp temporarily"

This reverts commit 6ebf5e14952b9fe176ae9f1f50b65640a7fa31f6.

Change-Id: I8b126c8e1615b60bea0782fe3f76c446a4e16567
m4: libaudioamp: Add initialization function stubs

Change-Id: I34aad7e268dbb59edb0d6c224f5f95cc75e405fa
m4: tfa9887: Fix race in checking whether or not to reconfigure

Multiple threads can request that we set_mode.  When
we check to see if we need to reconfigure the amp, make sure
that we are locked to avoid race conditions.

Change-Id: Ic247fdd8d1c55cd054053b9b7dc38d99a16cb33f
m4: tfa9887: Fix both speakers playing right channel

There was a little typo in the code that made left channel
not being played at all and right channel being played through two speakers.

Change-Id: I1f0328c77540df9cc075967ddac85d9598c91c5d
m4: Use custom libaudioamp

Change-Id: I04147700e5a2291d817799fe6cb22fcf817217d4
m4: Add TFA9887 config files to blob list

Change-Id: I2a14725dac494013d6e54d16b0a272cc8bfa625a
m4: Enable keymaster HAL

Change-Id: Ic1e202bd70f4c57de819cb6a9588190b1f39d01c
m4: Tighten up permissions to appease CTS

Change-Id: Ia2848de002d1a7fa3e9c5cf0f1ac93b05b76926f
m4: Mask the exec bit on firmware partitions

Change-Id: I47603d1398b6479142892935d5c7354e0f3977e6
m4: camera: Update HAL API versions and fix warnings

Change-Id: Ie1e401d982e19d1f7e45694c31cdbcbbfd890074