power: qpnp-qg: Update ESR estimation parameters

Do the following updates to ESR estimation parameters

- ESR mod count to 30
- ESR sample count to 3
- Use a minimum IBAT threshold to allow ESR during charge.
  This allows ESR estimation in taper.

While at it, use LAST_BURST_I register to report CURRENT_NOW,
this register averages internal and SMB (slave) current.

Change-Id: I95655f4ba2c20359afd44911bda969d0cc5624b3
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>