CONFIG_MIPS_MALTA is not available for the selected architecture x86.
Result is shown for architecture mips

Support for MIPS Malta board

modulename: fixup-malta.ko

configname: CONFIG_MIPS_MALTA

Linux/MIPS Kernel Configuration
└─>Machine selection
└─>Support for MIPS Malta board
In linux kernel since version 2.6.12 )
This enables support for the VR5000-based MIPS Malta evaluation
board.
source code:
arch/mips/pci/fixup-malta.c