kselftests/bpf: use ping6 as the default ipv6 ping binary if it exists

ping binary on some distros doesn't support "ping -6" anymore.

Signed-off-by: Li Zhijian <[e-mail]>
Acked-by: Song Liu <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>

tools/testing/selftests/bpf/test_skb_cgroup_id.sh

···
 	echo -n "Wait for testing link-local IP to become available "
 	for _i in $(seq ${MAX_PING_TRIES}); do
 		echo -n "."
-		if ping -6 -q -c 1 -W 1 ff02::1%${TEST_IF} >/dev/null 2>&1; then
+		if $PING6 -c 1 -W 1 ff02::1%${TEST_IF} >/dev/null 2>&1; then
 			echo " OK"
 			return
 		fi
···
 BPF_PROG_SECTION="cgroup_id_logger"
 BPF_PROG_ID=0
 PROG="${DIR}/test_skb_cgroup_id_user"
+type ping6 >/dev/null 2>&1 && PING6="ping6" || PING6="ping -6"
 
 main

tools/testing/selftests/bpf/test_sock_addr.sh

···
 
 ping_once()
 {
-	ping -${1} -q -c 1 -W 1 ${2%%/*} >/dev/null 2>&1
+	type ping${1} >/dev/null 2>&1 && PING="ping${1}" || PING="ping -${1}"
+	$PING -q -c 1 -W 1 ${2%%/*} >/dev/null 2>&1
 }
 
 wait_for_ip()