[rdkb][common][bsp][Refactor and sync kernel from openwrt]

[Description]
c831e5e1 [HIGH][kernel][mt7988][eth][Change reconfiguration criteria of the link down recovery handler for the USXGMII/SGMII]
273f0cd1 [kernel][mt7988][eth][Correct CPU next free and last free index of DMAD for TX ring debug command]
08bd7943 [kernel][mt7988][eth][Add XGMAC_MAC and XGMAC_STS to the dbg_regs command]

[Release-log]

Change-Id: Ide24540bec4a22b75bb114803c2d3aec10b10aa9
3 files changed