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

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 RUNNING from HALT state during
root hub initialization, interrupts are not handled by EHCI code in
ehci-hcd.c. This causes multiple interrupts getting triggered and
eventually leads to disabling of USB interrupt by kernel. Due to this,
enumeration of connected peripherals will fail.

CRs-Fixed: 385124
Change-Id: Icbfaebd4830e0e2c00c2f6531242417e6047950d
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>