qemu: command: Use JSON for parameters of -audiodev

'-audiodev' as a modern implementation based on QAPI already takes JSON
as the argument. Convert our code to use it directly.

The declaration of the QAPI types can be found in
'qemu.git/qapi/audio.json'.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

tests/qemuxml2argvdata/tpm-passthrough-crb.x86_64-latest.args

@@ -30,7 +30,7 @@ XDG_CONFIG_HOME=/tmp/lib/domain--1-TPM-VM/.config \
 -add-fd set=0,fd=1730 \
 -add-fd set=1,fd=1731 \
 -device '{"driver":"tpm-crb","tpmdev":"tpm-tpm0","id":"tpm0"}' \
--audiodev id=audio1,driver=none \
+-audiodev '{"id":"audio1","driver":"none"}' \
 -device '{"driver":"virtio-balloon-pci","id":"balloon0","bus":"pci.0","addr":"0x2"}' \
 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
 -msg timestamp=on