power: qpnp-smbcharger/fg: Keep BCL above LPM when CHG_LED is on

If charger going to sleep mode, the CHG_LED will be turned off. Keeping
BCL above LPM when CHG_LED is on to keep the charger in standby mode to
avoid messing up the CHG_LED behavior.

CRs-Fixed:951801
Change-Id: Ib9566f69d4cf70181f6ec8f3861be7d2f8e0cf00
Signed-off-by: Chunmei Cai <ccai@codeaurora.org>