fib: make netdev_switch_fib_ipv4_abort in header file static inline

When building without CONFIG_NET_SWITCHDEV,
netdev_switch_fib_ipv4_abort is defined in the header file. It must
be static inline to avoid build failure at link time.

Fixes: 8e05fd71 ("fib: hook IPv4 fib for hardware offload")
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NScott Feldman <sfeldma@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/switchdev.h

@@ -129,7 +129,7 @@ static inline int netdev_switch_fib_ipv4_del(u32 dst, int dst_len,
 	return 0;
 }
 
-void netdev_switch_fib_ipv4_abort(struct fib_info *fi)
+static inline void netdev_switch_fib_ipv4_abort(struct fib_info *fi)
 {
 }