nexthop: Fix type of event_type in call_nexthop_notifiers

Clang warns:

net/ipv4/nexthop.c:841:30: warning: implicit conversion from enumeration
type 'enum nexthop_event_type' to different enumeration type 'enum
fib_event_type' [-Wenum-conversion]
        call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh);
        ~~~~~~~~~~~~~~~~~~~~~~      ^~~~~~~~~~~~~~~~~
1 warning generated.

Use the right type for event_type so that clang does not warn.

Fixes: 8590ceedb7 ("nexthop: add support for notifiers")
Link: https://github.com/ClangBuiltLinux/linux/issues/1038
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/nexthop.c

@@ -37,7 +37,7 @@ static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = {
 };
 
 static int call_nexthop_notifiers(struct net *net,
-				  enum fib_event_type event_type,
+				  enum nexthop_event_type event_type,
 				  struct nexthop *nh)
 {
 	int err;