audio: disable default backends if -audio/-audiodev is used

Match what is done for other options, for example -monitor, and also
the behavior of QEMU 8.1 (see the "legacy_config" variable).  Require
the user to specify a backend if one is specified on the command line.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
4 files changed