power: smb5-lib: add support for s/w based health of parallel charger

For some parallel chargers(SMB1390/SMB1395) temperature and current
reporting is done via same h/w line, this sometimes leads to an unreliable
reporting of SMB DIE health via main charger. Fix this by moving to s/w
based reporting of SMB health by reading the SMB temperature via ADC
channel and comparing it with the predefined thresholds.

Change-Id: Ifc42a630d4fb6800b6d4f96656f03936d81abe8f
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>