[WAN]: fix section mismatch warning in sbni

In latest -mm sbni gives following warning: WARNING:
drivers/net/wan/sbni.o - Section mismatch: reference to \ .init.data:
from .text between 'init_module' (at offset 0x14ef) and \
'cleanup_module'

The warning is caused by init_module() calling a function declared
__init.  Declare init_module() __init too to fix warning.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wan/sbni.c

@@ -1495,8 +1495,7 @@ module_param(skip_pci_probe, bool, 0);
 MODULE_LICENSE("GPL");
 
 
-int
-init_module( void )
+int __init init_module( void )
 {
 	struct net_device  *dev;
 	int err;