ti_config_fragments: Clone audio_display.cfg for ARMv8

The one audio_display.cfg is used in both v7 and v8 maps. This prevents
more fine-grain pruning. For example v8 does not need OMAPDRM, but we
cannot remove it without removing it also from v7.

Make a clone of audio_display.cfg for use in the v8 map.

Signed-off-by: Andrew Davis <afd@ti.com>