JCG Y2 is an AC1300M router

Hardware specs:
  SoC: MediaTek MT7621AT
  Flash: Winbond W25Q128JVSQ 16MiB
  RAM: Nanya NT5CB128M16 256MiB
  2.4GHz: MT7615D 2x2
  5GHz: MT7615D 2x2
  Ethernet: 1 x WAN and 4 x LAN
  LED: POWER, INTERNET, 2.4G, 5G
  USB: 1 x 3.0
  Button: Reset

Flash instructions:
  Upload factory.bin in stock firmware's upgrade page.
Signed-off-by: NAmadeusGhost <amadeus@jmu.edu.cn>

* mtwifi: mt7615: fix multi-profile merge

Currently some settings like AutoChannelSelect, CountryRegion(ABand),
HT_BW/VHT_BW are not respected. This is due to wrong multi-profile
merging when l1profile.dat is not consistent with compiling flag
DEFAULT_5G_PROFILE.

5g profile should be put before 2g profile when DEFAULT_5G_PROFILE is
set.

References:
- https://github.com/coolsnowwolf/lede/blob/099439f051a8b2393554eb26cec2df074f653fae/package/lean/mt/drivers/mt7615d/Makefile#L52
- https://github.com/coolsnowwolf/lede/blob/099439f051a8b2393554eb26cec2df074f653fae/package/lean/mt/drivers/mt7615d/src/mt_wifi/os/linux/rt_profile.c#L211

* mtwifi: mt7615: fix reload

if wan iface set to apcli0 or apclii0 while wireless relay, add them to lan should be avoided (#5528)

* luci-app-mtwifi: add wifi relay support

Source code: Nossiac/mtk-openwrt-feeds
Based on commit 'wireless: wext: remove ndo_do_ioctl fallback'

* luci-app-mtwifi: fix ap-scan failed

* luci-app-mtwifi: show overview when relay is enabled

This reverts commit 23eb8b49.

* mtwifi: add mt7612 support (Thx TangHaili)

* mtwifi: mt7603/7612: disable autoload (Thx TangHaili)

* ramips: newifi3: use mtwifi

* luci-app-mtwifi: sync TangHaili's Source

Source code: https://github.com/MeIsReallyBa/mt7615-dbdc-linux5.4

只是认为 777 没有必要