power: Simplify display_boost checks

 - Remove 8084 check as all 8084s make use of the display boost
 - Convert the display_boost check to an soc_id check for 8974pro
 - Move display_boost (now soc_id) check to 8974's HAL

Change-Id: I237b9108e666f4cb0051d1c1bb22453d55ffcdc7
4 files changed