gnuradio : Update recipe to build for all machines.

Also updated the git repo address after recent changes in hosting.

The recipe failed to build for machines without neon as a tune feature.
The cmake config options have been changed so that it configures properly
now.

Also dropped documentation from build to work around a doc generation problem.

Test on armv7a, x86, and x86-64.

Signed-off-by: Philip Balister <philip@balister.org>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>