[PATCH] Fix arlan compilation with CONFIG_PROC_FS=n

From: Luiz Capitulino <lcapitulino@prefeitura.sp.gov.br>

when PROC_FS=n, arlan.h will define init_arlan_proc() and
cleanup_arlan_proc() as macros.  So, whitout the #ifdef/#endif here, we have
two definitions.

drivers/net/wireless/arlan-proc.c

@@ -1229,7 +1229,7 @@ static ctl_table arlan_root_table[] =
 //};
 
 
-
+#ifdef CONFIG_PROC_FS
 static struct ctl_table_header *arlan_device_sysctl_header;
 
 int __init init_arlan_proc(void)
@@ -1254,3 +1254,4 @@ void __exit cleanup_arlan_proc(void)
 	arlan_device_sysctl_header = NULL;
 
 }
+#endif