4A: don't pull agl-audio-plugin when 4A is enabled

4A: don't pull agl-audio-plugin when 4A is enabled

When agl-audio-4a-framework feature is enabled at aglsetup time, 4A audio
is enabled and legacy agl-audio-plugin used with GENIVI AudioManager must
not be pulled in images.

Change-Id: I23ff0ced9eff184718b47219e80f1f51db8b9fb8
Signed-off-by: Stephane Desneux <stephane.desneux@iot.bzh>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/12245
Tested-by: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-build: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>