Revert "m7-common: use QCOM hardware keystore"

This reverts commit da085b2fffe5db3c6d1bce13291931e456ce375a.

The hardware-backed keystore is broken in kitkat after
cccc0043b30824caee7e2c5899c288e67d91411c.

Change-Id: I2f20d3007ba7e737b2017634ed631dd6f44436e2
Merge "Revert "m7-common: use QCOM hardware keystore"" into cm-11.0