power: smb5-lib: use USB options in low ICL range

When USB ICL drops below 500mA, USB options show better input current
limit accuracy over USB high current mode. Make the change to always
try USB 2.0/3.0 options first for low ICL range, even for non-SDP
source type.

Change-Id: Iad5b369616b80e492de3daab10532e8cb2a67c82
Signed-off-by: Harry Yang <harryy@codeaurora.org>