Fix to return error code -ENOMEM from the alloc fail error handling
case instead of 0, as done elsewhere in this function.

Fixes: ecd29dab ("usb: dwc2: pci: Handle error cleanup in probe")
Reviewed-by: NGrigor Tovmasyan <tovmasya@synopsys.com>
Acked-by: NMinas Harutyunyan <hminas@synopsys.com>
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>