smb347_charger: fix battery status reporting logic for charger faults

smb347_charger: fix battery status reporting logic for charger faults

BZ: 34671

This patch checks for charger status register for determining the
battery charging status and reports Discharing/Charging/Not Charging/Full
accordingly.

This patch also adds the interrupt support for Safety Timer Expiration.

Change-Id: Ib7a34e5ceb1655228163a979db2cd3cc746a8d36
Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Reviewed-on: http://android.intel.com:8080/49618
Reviewed-by: Jena, TapanX <tapanx.jena@intel.com>
Reviewed-by: Tc, Jenny <jenny.tc@intel.com>
Tested-by: Kallappa Manjanna, MadhukumarX <madhukumarx.kallappa.manjanna@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>