thunderbolt: Use pseudo-random number as initial property block generation

As recommended by USB4 inter-domain service spec use pseudo-random value
instead of zero as initial XDomain property block generation value.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/xdomain.c

@@ -12,6 +12,7 @@
 #include <linux/kmod.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/prandom.h>
 #include <linux/utsname.h>
 #include <linux/uuid.h>
 #include <linux/workqueue.h>
@@ -1880,6 +1881,7 @@ int tb_xdomain_init(void)
 	tb_property_add_immediate(xdomain_property_dir, "deviceid", 0x1);
 	tb_property_add_immediate(xdomain_property_dir, "devicerv", 0x80000100);
 
+	xdomain_property_block_gen = prandom_u32();
 	return 0;
 }