USB: ice40-hcd: Put the gpio in sleep state during suspend

The bridge chip is completely power collapsed during suspend.
Put the gpio in sleep state during suspend and put them back
in default state during resume.

Change-Id: If326a44f463982a1674fe1f56be56c6972c2bc79
CRs-Fixed: 658474
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>