staging: ozwpan: Change error number.

Incorrect error number was returned here (EPERM), ENXIO is more
appropriate.

Signed-off-by: Rupesh Gujare <rupesh.gujare@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/ozwpan/ozcdev.c b/drivers/staging/ozwpan/ozcdev.c
index 03b41ee..50722ea 100644
--- a/drivers/staging/ozwpan/ozcdev.c
+++ b/drivers/staging/ozwpan/ozcdev.c
@@ -161,7 +161,7 @@
 		oz_pd_get(pd);
 	spin_unlock_bh(&g_cdev.lock);
 	if (pd == NULL)
-		return -1;
+		return -ENXIO;
 	eb = &pd->elt_buff;
 	ei = oz_elt_info_alloc(eb);
 	if (ei == NULL) {