power: smb5: fix watchdog configuration

Update the watchdog configuration logic to enable/disable
watchdog configuration based on software based step charging/jeita
state.
While at it, fix register offset of watchdog register.

Change-Id: I2138a85f52fafc556eef7e2743568608395df89b
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>