CONFIG_SH_RTS7751R2D is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

RTS7751R2D

modulename: fixups-rts7751r2d.ko

configname: CONFIG_SH_RTS7751R2D

Linux Kernel Configuration
└─>Board support
└─>RTS7751R2D
In linux kernel since version 2.6.12  
Select RTS7751R2D if configuring for a Renesas Technology
Sales SH-Graphics board.

source code:
arch/sh/drivers/pci/fixups-rts7751r2d.c