qemu: Upgrade 8.0.4 -> 8.1.0

qemu: Upgrade 8.0.4 -> 8.1.0

This upgrade isn't straighforward as upstream made changes. A pyenv
is now needed containing meson. This doesn't work for us for reasons
as yet unclear however it does mean we need python3native inherited
for that to stand a chance of working as otherwise host system
dependencies may be missing. For now, allow meson to work from our
sysroot via a patch. Our meson is always deterministic anyway so
we don't need their help for that.

The submodules approach used previously has changed, switch the options
for new ones to disable downloads and docs.

Some of the images binaries shipped for s390 show QA warnings for
relocations in code sections. Drop those binaries to avoid the QA
warnings since we don't need them anyway.

Drop a backported patch and refresh another.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>