power: smblib: suspend USBIN when ICL <= 25mA

USBIN will be suspended when outside consumer sets a low icl. Currently,
the condition is strictly <25mA, and it should be <=25mA.

Change-Id: I915fb736646cd43309c6a5520e5fdf4a9dd51efe
Signed-off-by: Harry Yang <harryy@codeaurora.org>