Kobject: change arch/x86/kernel/cpu/mcheck/mce_amd_64.c to use kobject_create_and_add

Make this kobject dynamic and convert it to not use kobject_register,
which is going away.

Cc: Jacob Shin <jacob.shin@amd.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>