power: smb1355: force enable clock while device is active

To optimize on power the SMB hardware disables the Bandgap/clock
when the charger is removed. When this happens, the SMB1355 IRQ
line stays stuck in its last known state. I.e. if there was an
interrupt pending (the IRQ line is low) and if the Bandgap/clock
gets disabled, the line stays stuck low forever causing a storm of
interrupts.

Fix this by forcing SMB1355 clock "on" as long as device is up and
and running and turn off the clock in ship-mode and shutdown path.

Change-Id: If01e07c63119b6af555ffd064d1055417c6b3e46
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>