power: Add specific powerhal for msm8937

* msm8937 is on the same CAF line along with msm8953 and msm8996 and also
  supports the MPCTL_V3 commands, in contrast to msm8952. Separate it from
  msm8952.

Change-Id: I58b0d7563cd3896ee4484ed0e0f38a6ef7eb01b2
2 files changed