xhci: Disable polling of shared hcd during suspend

During controller suspend and resume the roothub poll timer is
disabled and enabled only for primary hcd. If the roothub poll
timer is armed on shared hcd, controller suspends and then if
this timer function runs, it will result in unclocked register
access in xhci_hub_status_data().
So delete the timer even on shared hcd during suspend and
re-arm it during resume.

CRs-fixed: 696834

Change-Id: I3e0277984ed17311018681e86a4516e382dc9d4e
Signed-off-by: Azhar Shaikh <azhars@codeaurora.org>