max77693: Standardize the output of the "online" property

Return "0" when no power supply is present
Fixes CYAN-2138

Change-Id: I4a4391a454e8e1c5681f8a27ce498f77b4934e28
Revert "max77693: Standardize the output of the "online" property"

This reverts commit 1a05356029493b29f866cf04f7550243ef3ae687, the
enumerator breakage introduced by change Iafbd9fb45253b02d539ac0ba114f57b3bf9eeed4
can be reverted cleanly without further impact and it's a cleaner fix

Change-Id: I351c320f98691241fbe321a0b1ac54152802deb4
Merge branch 'cm-10.2' into martincz