mesa: move BBCLASSEXTEND out of the include file

mesa: move BBCLASSEXTEND out of the include file

We're going to have a new mesa-tools-native recipe include mesa.inc
soon. We don't need a target mesa-tools recipe for now so we'll go with
a native-only recipe which this BBCLASSEXTEND prevents us to do
properly, so let's move them to the recipes instead.

No intended change in behavior.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>