As Mesa refuses to compile if the "opengl" DISTRO_FEATURE isn't enabled,
mesa-driver-swrast has to be conditional in the QEMU machine defintions too.
(From OE-Core rev: 9951e1da6a755f9a46d3a595aa4c2f975aee8f46)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>