power: qpnp-charger: add battery presence detection selector

The SMBB peripheral allows batteries to be detected
via the BATT_ID, BATT_THM or both pins.

Add the qcom,bpd-detection property to allow customers
to determine which method should be chosen to detect
a valid battery.

Change-Id: I474f8f4d5aa3ce2a1d73b20a491c0bd31047aeb3
Signed-off-by: David Keitel <dkeitel@codeaurora.org>