RPi4B: emmc2bus dma-range handling does not track the boot-time-FDT (u-boot based booting)

[Klaus Cucinauomo]

> Am 08.10.2020 um 11:01 schrieb Mark Millard via freebsd-arm <freebsd-arm at freebsd.org>:
> 
> 
> The old u-boot/DTB combination in use does not have emmc2bus.
> And, even if it did, FreeBSD would not use ……….

… and the new 2020.10- combinations will even be more annoying…
While I meanwhile e.g. could boot the 4GB off of xhci, it hangs in DeviceTree,
Depending on GUESSED ;-) combinations and DeviceTree-patches in src .
There have to be necessary  adjustments which are even not yet upstreamed in u-boot 
(depending on hw-revisions)…and so on ...
I doubt that anyone really will take explicitly time consuming care of all that annoying RPI4-crap.
I don't see any other way than targeting minimum 1 developer(better more) ONLY to the RPI-platform 
for a  time period… other than leaving it crappy as is and to be happy that it nevertheless 
is a working fbsd-gadget :-)