Revert "UsbManager: Add the support of USB charging only function"

This change is bogus and breaks the USB connection mode UX.
There is no reason to change the current USB connection
behaviour, hence revert to AOSP behaviour for this.

This commit also depends on the Settings commit with
the change-id Iad7d0811b7dcffe78c734c073dceb6c054fcea11.

This reverts commit a694b103.

Change-Id: Ia61b341d5cd403f165d24257bab4148b1d9f4193