power: pm8921-charger: report correct online status when disabled

The current code returns that a charger is not connected when charging
is disabled. This causes applications that depend on charger's presence
(not necessarily charging) to fail.

Fix this by returning the correct online status.

Change-Id: I0aa523321f1eed4a0a5461b1a894452f77e6ff99
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>