usb: cdns3: ep0: fix some endian issues

[ Upstream commit 9f81d45c79271def8a9b90447b04b9c6323291f9 ]

It is found by sparse.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>