Check if dwc is NULL before accessing dwc->num_ports in the
dwc3_qcom_suspend function. Prevent a potential NULL pointer
dereference when the dwc structure is not properly initialized.

Change-Id: I0e673ddd59946e9c1a67d3de09db78653c0645bc
Signed-off-by: Faisal Hassan <faisal.hassan@oss.qualcomm.com>