[][HIGH][kernel][common][hnat][Add releases the reference to ct]

[Description]
Add hnat releases the reference to conntrack.
Without this patch, conntrack will full in long time test.

[Release-log]
N/A

Change-Id: I21d2df8100de7a8cf7f11ec267e8fff3701cea2d
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/9779345
diff --git a/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_hnat/hnat_debugfs.c b/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_hnat/hnat_debugfs.c
index ab68eac..49554b8 100644
--- a/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_hnat/hnat_debugfs.c
+++ b/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_hnat/hnat_debugfs.c
@@ -1149,6 +1149,8 @@
 			/* avoid compiler warnings */
 			if (tuple.dst.protonum == IPPROTO_TCP)
 				nf_conntrack_tcp_established(ct);
+
+			nf_ct_put(ct);
 		}
 	}