power: smb135x-charger: Report the USB not connected status at init

The USB driver expects the charger driver to report the initial status
of the USB even if it is not connected. Report the same when the charger
driver is being initialized.

Change-Id: I95d7b119fc965afe957702e255fc376729e18857
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>