power: smb1390: Add IREV IRQ handler to toggle switcher

Added support of toggling switcher, whenever IREV IRQ is triggered
as because the switcher is expected to be restarted to deal with
the load release case.

CRs-Fixed: 2200344
Change-Id: Ia2139d00965544e1dbb6d33685346dfbe5293337
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>