net/mlx5: fix kvfree of uninitialized pointer spec

Currently when a call to  esw_vport_create_legacy_ingress_acl_group
fails the error exit path to label 'out' will cause a kvfree on the
uninitialized pointer spec.  Fix this by ensuring pointer spec is
initialized to NULL to avoid this issue.

Addresses-Coverity: ("Uninitialized pointer read")
Fixes: 10652f39 ("net/mlx5: Refactor ingress acl configuration")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/eswitch.c

@@ -1253,7 +1253,7 @@ static int esw_vport_ingress_config(struct mlx5_eswitch *esw,
 	struct mlx5_flow_destination drop_ctr_dst = {0};
 	struct mlx5_flow_destination *dst = NULL;
 	struct mlx5_flow_act flow_act = {0};
-	struct mlx5_flow_spec *spec;
+	struct mlx5_flow_spec *spec = NULL;
 	int dest_num = 0;
 	int err = 0;
 	u8 *smac_v;