cmd/bootdev: print readable status code

device_probe() called by the 'bootdev info' command
returns 0 or a negative error code.

itoa() cannot print negative numbers.

Convert the error code to a positive number.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/cmd/bootdev.c b/cmd/bootdev.c
index 5b1efaa..a657de6 100644
--- a/cmd/bootdev.c
+++ b/cmd/bootdev.c
@@ -99,7 +99,7 @@
 
 	printf("Name:      %s\n", dev->name);
 	printf("Sequence:  %d\n", dev_seq(dev));
-	printf("Status:    %s\n", ret ? simple_itoa(ret) : device_active(dev) ?
+	printf("Status:    %s\n", ret ? simple_itoa(-ret) : device_active(dev) ?
 		"Probed" : "OK");
 	printf("Uclass:    %s\n", dev_get_uclass_name(dev_get_parent(dev)));
 	printf("Bootflows: %d (%d valid)\n", i, num_valid);