[][update CDM guard band follow DE suggestion]

[Description]
Change CDM guard band RSV_BUF from 0x40 to 0x 80
    - default 0x40 may cause xDMA hang

[Release-log]
N/A

Change-Id: I35709661d4715141b153c693d6d834e52e39f5d6
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5862368
diff --git a/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index a31c4f6..4cd18bc 100755
--- a/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -364,7 +364,7 @@
 #define MTK_CHK_DDONE_EN	BIT(28)
 #define MTK_DMAD_WR_WDONE	BIT(26)
 #define MTK_WCOMP_EN		BIT(24)
-#define MTK_RESV_BUF		(0x40 << 16)
+#define MTK_RESV_BUF		(0x80 << 16)
 #define MTK_MUTLI_CNT		(0x4 << 12)
 
 /* QDMA Reset Index Register */