petalogix-ml605: Set the MicroBlaze CPU version to 8.10.a

Set the MicroBlaze CPU version to 8.10.a avoiding a runtime
warning due to an unset CPU version.
Reviewed-by: NPeter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>

hw/microblaze/petalogix_ml605_mmu.c

@@ -81,6 +81,7 @@ petalogix_ml605_init(MachineState *machine)
 
     /* init CPUs */
     cpu = MICROBLAZE_CPU(object_new(TYPE_MICROBLAZE_CPU));
+    object_property_set_str(OBJECT(cpu), "8.10.a", "version", &error_abort);
     /* Use FPU but don't use floating point conversion and square
      * root instructions
      */