net: ipv4: fib_semantics: fix uninitialized variable

fix an uninitialized variable:

  CC      net/ipv4/fib_semantics.o
net/ipv4/fib_semantics.c: In function 'fib_check_nh_v4_gw':
net/ipv4/fib_semantics.c:1027:12: warning: 'err' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (!tbl || err) {
            ^~
Signed-off-by: Enrico Weigelt <info@metux.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/fib_semantics.c

@@ -964,7 +964,7 @@ static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
 {
 	struct net_device *dev;
 	struct fib_result res;
-	int err;
+	int err = 0;
 
 	if (nh->fib_nh_flags & RTNH_F_ONLINK) {
 		unsigned int addr_type;