modprobe n2 with no parameters or no such devices
will get confusing error message.

# modprobe n2
...  Kernel does not have module support

This patch replaces return code from -ENOSYS to -EINVAL.

Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

 drivers/net/wan/n2.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
Signed-off-by: Jeff Garzik <jeff@garzik.org>