ipq8074: add Netgear RBK850 BDF

[mmlr]

For use in Netgear RBR850 and RBS850.

Extracted from GPL sources of firmware version 7.2.8.5:

package/base-files/files/lib/firmware/IPQ8074/ETSI/bdwlan.b215

The file is identical to the one under the FCC subdirectory but different from all the others.

ath11k-bdencoder -i board-netgear_rbk850.ipq8074
FileSize: 131180
FileCRC32: bbf96009
FileMD5: 07b13415e018add79b60ca59d7d8cff8
BoardNames[0]: 'bus=ahb,qmi-chip-id=0,qmi-board-id=255,variant=Netgear-RBK850' BoardLength[0]: 131072
BoardCRC32[0]: 7d33a92a
BoardMD5[0]: efd6c3d34a5b534db612a5a6a930a773

[piter75]

hey @robimarko, could we get this in?

I would like to continue the work @mmlr has started in openwrt/openwrt#22159.
It would be much easier with the BDF file already in.

[sbs44]

+1 on merging this. I've been running 283acdd on 1x RBR850 and 2x RBS850 since May alongside mmlr's device support... 2.4GHz and both 5GHz radios come up correctly with it. @matteoagosti has reported the same on two RBS850s.

It's currently the blocker for @piter75's openwrt/openwrt#24906, which continues mmlr's work and is otherwise ready for wider testing.

@robimarko - anything needed from us to move it along?

[matteoagosti]

Confirming from the satellite side: I have two RBS850s running with this BDF, and all three radios come up correctly on both — 2.4 GHz on channel 1 at HE20, the low 5 GHz band on channel 36 at HE80 carrying the household clients, and the high 5 GHz band on channel 100 at HE80 carrying an 802.11s mesh between the units. This is daily home use rather than a bench setup, with one of them also serving DHCP and DNS for everything else in the house, and the current unit is eight days into an uninterrupted run on r31989+1-71deb5b6d5 with clients on both AP bands as I write this. No calibration or throughput oddities to report on either.

Nothing needed from me to move it along, and happy to test anything specific if it helps. It would be good to see this land, since @piter75's openwrt/openwrt#24906 is otherwise ready for wider testing and this is what stands in front of it.

[robimarko]

Thanks! Rebased on top of main and merged!