power: smb5-lib: unvote SW_ICL_MAX_VOTER for USB_ICL in SRC to SNK swap

During PR_SWAP from sink to source, the sink device would detect a
detach event and in the handler SW_ICL_MAX_VOTER puts a vote in
USB_ICL votable for 100 mA. After that, if the device receives a
PR_SWAP request to transit from source to sink and when the transition
is in progress, the new sink device would receive an attach event.
At this event, the vote from SW_ICL_MAX_VOTER on USB_ICL votable
should be removed. Fix it.

Change-Id: I772bea9bdfcf6f4a82ae502e5f8148fb7d152f51
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>