power: smb1360: add a property to select the stat pin irq configuration

The stat pin irq supports pulse signals as well as static level signals
when interrupt triggered. Add a property to select between the two
configurations.

Change-Id: I533bcab0f0c0255d1d41fbe2f898451072772a26
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>