power: supply: qbg: Fixes in QBG driver

Add changes required in QBG driver after validation on pm5100.
1. Add sample time for different QBG modes.
2. Store batt id and essential param revid after each FIFO processing and
   at startup use that data to decide whether to load SDAM data or not.
3. PM5100 ADC reports the batt_id directly, drop the voltage based
   conversion logic.
4. Fix the LSB value for current.

Change-Id: Ib51f8c5e48c89ee7bf60e5ee9a6c575617461a02
Signed-off-by: Shyam Kumar Thella <sthella@codeaurora.org>