net: mediatek: add support for MediaTek MT7981/MT7986

This patch adds support for MediaTek MT7981 and MT7986. Both chips uses
PDMA v2.

Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Tested-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
diff --git a/drivers/net/mtk_eth.h b/drivers/net/mtk_eth.h
index 236c498..1382ccb 100644
--- a/drivers/net/mtk_eth.h
+++ b/drivers/net/mtk_eth.h
@@ -36,6 +36,8 @@
 
 #define MT7623_CAPS  (MTK_GMAC1_TRGMII)
 
+#define MT7986_CAPS  (MTK_NETSYS_V2)
+
 /* Frame Engine Register Bases */
 #define PDMA_V1_BASE			0x0800
 #define PDMA_V2_BASE			0x6000
@@ -72,6 +74,9 @@
 #define SGMSYS_QPHY_PWR_STATE_CTRL	0xe8
 #define SGMII_PHYA_PWD			BIT(4)
 
+#define SGMSYS_QPHY_WRAP_CTRL		0xec
+#define SGMII_PN_SWAP_TX_RX		0x03
+
 #define SGMSYS_GEN2_SPEED		0x2028
 #define SGMSYS_GEN2_SPEED_V2		0x128
 #define SGMSYS_SPEED_2500		BIT(2)