rtw88 import to main

Hi,

I've just pushed Realtek's rtw88 driver into the tree along with
firmware to support it and man pages.  Station mode only.


CAVEAT-0:  Even though the MFC reminder is set, I'll probably not
merge it this quickly into the stable/13 branch (see CAVEAT-1).
If you want to do so yourself, you currently also need
86220d3cbd500b1018dcdabb0ba70644db438cfd if you are on i386 (I'll
merge that in two days).  I'll also keep merging anything else
which improves things.   Otherwise it's just the three commits to
cherry-pick.


CAVEAT-1:  if you have more than 4GB of main memory, the driver will
likely fail to load firmware or work.  Sounds silly these days but hey.

The reason for that is between LinuxKPI and busdma as I understand
it currently and you can follow the problem by also applying
https://reviews.freebsd.org/D34715 and checking the new
compat.linuxkpi.lkpi_pci_nseg1_fail increases to > 0 when you try
to load the driver.

We'll keep pondering and I'll likely post (elsewhere) more about this
the next days.  Depending on the outcome of discussions we'll see how
to solve that problem (I am currently thinking how much else it may
affect and whether to hack the driver or FreeBSD to fix it).

HINT-1: If you are still curious (and given you made it here you are!)
you can try booting with
 	hw.physmem="4G"	# I believe is the right tuneable
in loader.conf (which should limit your computers ability to do anything
interesting these days) but may make rtw88 work (and that would
be a report I'd be very interested in along with the PCI IDs and full
dmesg if you wish).  I know from one person who has tried successfully.
I also tried on a 2G amd64 where this worked.  My 64GB arm64 is still
not happy even with this but that's probably another story.


SUMMARY: I've added mentions of this to
 	https://wiki.freebsd.org/WiFi/Rtw88
as well.


CAVEAT-2: because of CAVEAT-1 testing so far has been limited so
anything you can add will be appreciated.  See HINT-1.


Happy April 1st...  oh I am not supposed to say that as this is real..tek?

/bz

-- 
Bjoern A. Zeeb                                                     r15:7