[][kernel][mt7988][eth][Revert memory high threshold setting for the CDM2]

[Description]
Revert memory high threshold setting for the CDM2.

The driver has adjusted the guard band setting of the CDM2 to 2KB by
modifying RESV_BUF of the QDMA. Thus, there is no need to adjust the
memory high threshold for the CDM2.

[Release-log]
N/A


Change-Id: Ib0c631b25662ec72c091b4cf423c3655d39b6a11
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/9716033
diff --git a/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 85de23f..a5765d7 100644
--- a/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/21.02/files/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -4684,7 +4684,6 @@
 		mtk_w32(eth, 0x00600009, PSE_IQ_REV(8));
 
 		/* GDM and CDM Threshold */
-		mtk_w32(eth, 0x00000004, MTK_CDM2_THRES);
 		mtk_w32(eth, 0x08000707, MTK_CDMW0_THRES);
 		mtk_w32(eth, 0x00000077, MTK_CDMW1_THRES);