Link the Object base class and the module infrastructure for class
registration. Introduce $(universal-obj-y) for objects that are more
common than $(common-obj-y), so that those only get built once.

Call QOM module init for type registration.
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Cc: Anthony Liguori <anthony@codemonkey.ws>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>