qcacmn: Add SAR power limit configuration

There is a regulatory requirement for Specific Absorption
Rate (SAR) whereby the phone transmit power is reduced
when it is determined that the phone is in close
proximity to the body.
Implement a vendor command interface to set SAR power
limts dynamically.

Change-Id: I0a214a2af780e9dd8c381c4e9eaa7d8cab6ef853
CRs-Fixed: 1098102
5 files changed