bitbake.conf: add 'gobject-introspection-data' to DISTRO/MACHINE_FEATURES_BACKFILL

bitbake.conf: add 'gobject-introspection-data' to DISTRO/MACHINE_FEATURES_BACKFILL

This means that introspection data will be generated using qemu by default.

If this causes trouble (qemu does not always emulate target architectures
perfectly), then add
MACHINE_FEATURES_BACKFILL_CONSIDERED = "gobject-introspection-data"
to machine configuration or
DISTRO_FEATURES_BACKFILL_CONSIDERED = "gobject-introspection-data"
to distro configuration.

(From OE-Core rev: 7eb19aa29f40c10b0ed9e9c384652dbc9d185088)

Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>