usb: cdns3: remove redundant assignment to ret on error exit path

usb: cdns3: remove redundant assignment to ret on error exit path

In the case where an allocation fails for priv_ep ret is
assigned -ENOMEM and the code exits via the exit path 'err'.
The exit path returns -ENOMEM without using variable ret, so
the assingment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20190902184334.27406-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>