CONFIG_PPC_SMLPAR is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Support for shared-memory logical partitions

configname: CONFIG_PPC_SMLPAR

Linux Kernel Configuration
└─>Support for shared-memory logical partitions
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
Select this option to enable shared memory partition support.
With this option a system running in an LPAR can be given more
memory than physically available and will allow firmware to
balance memory across many LPARs.