power: smb1390: Override ILIM in taper only for CC mode

Do not override ILIM with the max value in CV charging mode as it might
lead to adaptors collapsing. Setting main's ICL to 500 mA is also only
applicable in the case of CC charging mode, so mark that appropriately.

Change-Id: Ifa54094186eb205f3acf3335a54d267573d4d651
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>