usb: class: cdc-wdm: return the correct errno code

usb: class: cdc-wdm: return the correct errno code

The "rv" is initialized to "-ENOMEM", because "rv" is re-assigned to
"-EINVAL", when kmalloc & usb_alloc_urb failed, the return value should
return "-ENOMEM" rather than "-EINVAL",so the "rv" assignment is placed
in the position where usb_endpoint_is_int_in is false.

Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Junlin Yang <yangjunlin@yulong.com>
Link: https://lore.kernel.org/r/20210621132415.2341-1-angkery@163.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>