[NET]: Fix GCC4 compile error: sysctl in linux/if_ether.h

The following is generated when compiling a
recent (2.6.14-rc2-git5) kernel configured for
ARM, with GCC4.

CC init/main.o
In file included from include/linux/netdevice.h:29,
from include/net/sock.h:48,
from init/main.c:50:
include/linux/if_ether.h:114: error: array type has incomplete element type

It seems that if CONFIG_SYSCTL is not set, then
the compiler will throw an error due to the definition
of the ether_table[] array

Attached is a solution to the problem

Signed-off-by: Ben Dooks <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/if_ether.h

···
 	return (struct ethhdr *)skb->mac.raw;
 }
 
+#ifdef CONFIG_SYSCTL
 extern struct ctl_table ether_table[];
+#endif
 #endif
 
 #endif	/* _LINUX_IF_ETHER_H */