kern/ieee1275/init: Convert plain numbers to constants in Vec5

kern/ieee1275/init: Convert plain numbers to constants in Vec5

This patch converts the plain numbers used in Vec5 properties to constants.

1. LPAR: Client program supports logical partitioning and
   associated hcall()s.
2. SPLPAR: Client program supports the Shared
   Processor LPAR Option.
3. CMO: Enables the Cooperative Memory Over-commitment Option.
4. MAX_CPU: Defines maximum number of CPUs supported.

Signed-off-by: Avnish Chouhan <avnish@linux.vnet.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>