usb: cdns3: Fixes for sparse warnings

Patch fixes the following warnings:
cdns3-gadget.c:1203: sparse: warning: incorrect type
                     in assignment (different base types)
cdns3-gadget.c:1203: sparse:  expected restricted __le32 [usertype] length
cdns3-gadget.c:1203: sparse:  got unsigned long
cdns3-gadget.c:1250: sparse: warning: invalid assignment: |=
cdns3-gadget.c:1250: sparse:  left side has type restricted __le32
cdns3-gadget.c:1250: sparse:  right side has type unsigned long
cdns3-gadget.c:1253: sparse: warning: invalid assignment: |=
cdns3-gadget.c:1253: sparse:  left side has type restricted __le32
cdns3-gadget.c:1253: sparse:  right side has type unsigned long
cdns3-ep0.c:367: sparse: warning: restricted __le16 degrades to integer
cdns3-ep0.c:792: sparse: warning: symbol 'cdns3_gadget_ep0_ops' was not
                                  declared. Should it be static?

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>