Instead of spreading the ptest enabling over the recipe, just add a
PACKAGECONFIG to enable the installed tests. Whether this is enabled respects
PTEST_ENABLED by default, so it always disabled in native and nativesdk builds.
This means we can remove the conditional dependency on dbus, all the conditional
enabling of installed tests, and clean up EXTRA_OEMESON.
Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
