mcb: fix a double free bug in chameleon_parse_gdd()

In chameleon_parse_gdd(), if mcb_device_register() fails, 'mdev'
would be released in mcb_device_register() via put_device().
Thus, goto 'err' label and free 'mdev' again causes a double free.
Just return if mcb_device_register() fails.

Fixes: 3764e82e5150 ("drivers: Introduce MEN Chameleon Bus")
Cc: stable <[e-mail]>
Signed-off-by: Haoxiang Li <[e-mail]>
Signed-off-by: Johannes Thumshirn <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/mcb/mcb-parse.c

···
 
 	ret = mcb_device_register(bus, mdev);
 	if (ret < 0)
-		goto err;
+		return ret;
 
 	return 0;