tests/qemu-iotests/312: Mark "quorum" as required driver

tests/qemu-iotests/312: Mark "quorum" as required driver

"quorum" is required by iotest 312 - if it is not compiled into the
QEMU binary, the test fails. Thus list "quorum" as required driver
so that the test gets skipped in case it is not available.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230104114601.269351-1-thuth@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>