uhd : Add patch to fix NEON detection on hard float systems.

Backport from uhd/maint.

Signed-off-by: Philip Balister <philip@balister.org>
Add devmem2 to images.

Yes, I need to re-factor the image recipes.

Signed-off-by: Philip Balister <philip@balister.org>
uhd-firmware : Do not damage the unpacked source.

If the recipe run do_install again, without do_unpack, the build failed since
do_install was deleting directories from S. Stop doing that. This led to maddening,
seemingly random build failures.

Signed-off-by: Philip Balister <philip@balister.org>