usb: cdnsp: fixes undefined reference to cdns_remove

Patch fixes the following errors:
ld: drivers/usb/cdns3/cdnsp-pci.o: in function `cdnsp_pci_remove':
cdnsp-pci.c:(.text+0x80): undefined reference to `cdns_remove'
ld: drivers/usb/cdns3/cdnsp-pci.o: in function `cdnsp_pci_probe':
cdnsp-pci.c:(.text+0x34c): undefined reference to `cdns_init'

Issue occurs for USB/CDNS3/CDNSP kernel configuration:
CONFIG_USB=m
CONFIG_USB_CDNS_SUPPORT=y
CONFIG_USB_CDNS3=m
CONFIG_USB_CDNS3_PCI_WRAP=m
CONFIG_USB_CDNSP_PCI=y

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Peter Chen <peter.chen@kernel.org>