[][Kernel][mt7988][eth][Add XFI MAC debug command]

[Description]
Add new debug command for XFI MAC, which can be used to
diagnose both external 10G phy and internal 2.5G phy path.

- Usage:
	- cat /proc/mtketh/xfi_cnt

- What the command can show includes:
	- TX_PKT_CNT		(packet count)
	- TX_ETH_CNT		(Ethernet frame)
	- TX_PAUSE_CNT		(pause frame)
	- TX_BYTE_CNT		(byte count)
	- TX_UC_PKT_CNT		(unicast)
	- TX_MC_PKT_CNT		(multicast)
	- TX_BC_PKT_CNT		(broadcast)
	- RX_PKT_CNT		(packet count)
	- RX_ETH_CNT		(Ethernet frame)
	- RX_PAUSE_CNT		(pause frame)
	- RX_LEN_ERR_CNT	(length error)
	- RX_CRC_ERR_CNT	(crc error)
	- RX_UC_PKT_CNT		(unicast)
	- RX_MC_PKT_CNT		(multicast)
	- RX_BC_PKT_CNT		(broadcast)
	- RX_UC_DROP_CNT	(unicast drop)
	- RX_BC_DROP_CNT	(broadcast drop)
	- RX_MC_DROP_CNT	(multicast drop)
	- RX_ALL_DROP_CNT	(total drop)

If without this patch, we aren't able to obtain
XFI MAC TX/RX MIB information.

[Release-log]
N/A


Change-Id: I9378910a3bc0298dfe1f1c43baa1d0ec056f06b3
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7034012
2 files changed