audio/dbus: fix building

audio/dbus: fix building

Commit c9c847481 broken dbus audio module compilation with bad
'CONFIG_GIO' usage. Furthermore, it implied extra dependency on audio
module which aren't necessary.

The problem was that 'dbus_display' is not correctly automatically set
on MacOS, because opengl dependency wasn't taken into account.

Fixes: c9c847481 ("audio/dbus: Fix building with modules on macOS")
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220622154918.560870-1-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>