power: qpnp-charger: Use simpler ifdefs

Change-Id: I1986826c5d2f30f04313b5ae4d7426ecfaac8053
power: qpnp-charger: Properly report offline state for DC

* Actually generate uevents for USB-DC power supply.
* QPNP-DC power supply online status checks for USB DCP on
  Oppo devices. Make sure USB is plugged in when checking online
  status.

Change-Id: Ie80ad7629bea59d896bf95123ac12939c6539a23