Add HAL APIs and configurations for Tx power limits

To lower the instantaneous battery current draw of WiFi, we provide
a way to allow PowerManager to enable/disable Tx power limits.
In this CL,
we define an API in WiFi HAL, and can be referenced by Broadcom HAL.

Bug: 215193418
Test: New APIs work fine
Change-Id: I907687a4d71f48869617edc6e013639dfbccb851
1 file changed