USB: EHCI: Fix bug in updating root hub state during suspend

commit e8799906 (USB: EHCI: remove usages of hcd->state) removed the
hcd->state usage in EHCI driver.  Instead rh_state field of ehci_hcd
struct should be used. But the current code is still using
hcd->state. This bug is introduced during 3.4 kernel porting.

If rh_state field is not updated to SUSPEND during root hub suspend,
the root hub will not be resumed upon device connection or remote wakeup.

Change-Id: Id47e7c650c03cda2e7be00be4e8b92a47257fc6a
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>