CONFIG_MACH_REALVIEW_PB11MP is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Support RealView/PB11MPCore platform

modulename: realview_pb11mp.ko

configname: CONFIG_MACH_REALVIEW_PB11MP

Linux Kernel Configuration
└─>RealView platform type
└─>Support RealView/PB11MPCore platform
In linux kernel since version 2.6.26 (release Date: 2008-07-13)  
Include support for the ARM(R) RealView MPCore Platform Baseboard.
PB11MPCore is a platform with an on-board ARM11MPCore and has
support for PCI-E and Compact Flash.

source code:
arch/arm/mach-realview/realview_pb11mp.c