power: smb1390-psy: add support to expose chip version

Add support to read chip version from rev-id peripheral and
expose it to userspace via power_supply property.

Change-Id: Ic522ec7dd7e6849f9f599cfba07e22c59878ce84
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>