hw: Fix crash that happens when introspecting scsi-block on older machine types

"make check SPEED=slow" is currently failing the device-introspect-test on
older machine types since introspecting "scsi-block" is causing an abort:

 $ ./qemu-system-x86_64 -M pc-q35-8.0 -monitor stdio
 QEMU 9.0.50 monitor - type 'help' for more information
 (qemu) device_add scsi-block,help
 Unexpected error in object_property_find_err() at
 ../../devel/qemu/qom/object.c:1357:
 can't apply global scsi-disk-base.migrate-emulated-scsi-request=false:
 Property 'scsi-block.migrate-emulated-scsi-request' not found
 Aborted (core dumped)

The problem is that the compat code tries to change the
"migrate-emulated-scsi-request" property for all devices that are
derived from "scsi-block", but the property has only been added
to "scsi-hd" and "scsi-cd" via the DEFINE_SCSI_DISK_PROPERTIES macro.

Thus let's fix the problem by only changing the property on the devices
that really have this property.

Fixes: b4912afa5f ("scsi-disk: Fix crash for VM configured with USB CDROM after live migration")
Message-ID: <20240703090904.909720-1-thuth@redhat.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/core/machine.c

@@ -36,7 +36,8 @@
 
 GlobalProperty hw_compat_9_0[] = {
     {"arm-cpu", "backcompat-cntfrq", "true" },
-    {"scsi-disk-base", "migrate-emulated-scsi-request", "false" },
+    { "scsi-hd", "migrate-emulated-scsi-request", "false" },
+    { "scsi-cd", "migrate-emulated-scsi-request", "false" },
     {"vfio-pci", "skip-vsc-check", "false" },
     { "virtio-pci", "x-pcie-pm-no-soft-reset", "off" },
     {"sd-card", "spec_version", "2" },