[FS#691] 5Ghz radio detected as 2.4Ghz and not-functional on Asus RP-N53 and Buffalo WHR-600D (Ralink RT5592)

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - kbios (kbios) 

Attached to Project - LEDE Project
Summary - 5Ghz radio detected as 2.4Ghz and not-functional on Asus RP-N53 and Buffalo WHR-600D (Ralink RT5592)
Task Type - Bug Report
Category - Kernel
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - These two devices have a 2.4 Ghz radio integrated in the MT7620 SoC, and a pcie 5Ghz radio.
The 5Ghz radio is identified in dmesg as 

[    9.832680] ieee80211 phy0: rt2x00_set_rt: Info - RT chipset 5592, rev 0222 detected
[    9.851675] ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 0001 detected
[    9.866116] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'

and in lspci as 

01:00.0 Network controller [0280]: Ralink corp. RT3091 Wireless 802.11n 1T/2R PCIe [1814:3091]
        Subsystem: Ralink corp. RT3091 Wireless 802.11n 1T/2R PCIe [1814:3091]
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-