selftests: ip_local_port_range: use XFAIL instead of SKIP

SCTP does not support IP_LOCAL_PORT_RANGE and we know it,
so use XFAIL instead of SKIP.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/ip_local_port_range.c

@@ -365,9 +365,6 @@ TEST_F(ip_local_port_range, late_bind)
 	__u32 range;
 	__u16 port;
 
-	if (variant->so_protocol == IPPROTO_SCTP)
-		SKIP(return, "SCTP doesn't support IP_BIND_ADDRESS_NO_PORT");
-
 	fd = socket(variant->so_domain, variant->so_type, 0);
 	ASSERT_GE(fd, 0) TH_LOG("socket failed");
 
@@ -414,6 +411,9 @@ TEST_F(ip_local_port_range, late_bind)
 	ASSERT_TRUE(!err) TH_LOG("close failed");
 }
 
+XFAIL_ADD(ip_local_port_range, ip4_stcp, late_bind);
+XFAIL_ADD(ip_local_port_range, ip6_stcp, late_bind);
+
 TEST_F(ip_local_port_range, get_port_range)
 {
 	__u16 lo, hi;