xhci: hsic: Fix NULL pointer dereference in mxhci_hsic_hub_control

Primary HCD pointer is set when initializing SS HCD structure.
There is possibility of hub_port_staus getting called for HS
root hub when primary HCD pointer is not initialized. Hence
do not access primary HCD pointer in mxhci_hsic_hub_control.

Change-Id: Ie91a87b1a2d6757410f1f5c9c6010e2099c29420
CRs-Fixed: 674442
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>