selftests: mlxsw: devlink_trap_tunnel_ipip: Send a full-length key

As part of adding same test for GRE tunnel with IPv6 underlay, missing
bytes for key were found.

mausezahn does not fill zeros between two colons, so send them
explicitly. For example, use "00:00:00:E9:" instead of ":E9:"
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/mlxsw/devlink_trap_tunnel_ipip.sh

@@ -223,7 +223,8 @@ decap_error_test()
 	no_matching_tunnel_test "Decap error: Source IP check failed" \
 		192.0.2.68 "0"
 	no_matching_tunnel_test \
-		"Decap error: Key exists but was not expected" $sip "2" ":E9:"
+		"Decap error: Key exists but was not expected" $sip "2" \
+		"00:00:00:E9:"
 
 	# Destroy the tunnel and create new one with key
 	__addr_add_del g1 del 192.0.2.65/32
@@ -235,7 +236,8 @@ decap_error_test()
 	no_matching_tunnel_test \
 		"Decap error: Key does not exist but was expected" $sip "0"
 	no_matching_tunnel_test \
-		"Decap error: Packet has a wrong key field" $sip "2" "E8:"
+		"Decap error: Packet has a wrong key field" $sip "2" \
+		"00:00:00:E8:"
 }
 
 trap cleanup EXIT