battery: fix 0mA ICL not suspending charger

There is a bug in usb ICL (input current limit) votable callback
where it fails to set the current on main charger if the new value
is lower than the settled value.

Fix it.

Change-Id: I8e8e1c16772eabe9f411c3de5460ca581a3a5d37
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>