power: smb5: add support for ICL override

In TypeC mode charger hardware follows a predefined
ICL configuration and does not honor input limit configured
in ICL configuration register, this limits the ability to
control ICL of charger specifically in case of USBIN-USBIN based
parallel charging where ICL is split between main and parallel
charger or in situation where ICL de-rating is required.

Change-Id: I446cf1460169a980c75c1413314fa53d93f7f57d
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>