CONFIG_MACH_ARMADA_370_XP is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_MACH_ARMADA_370_XP (not configurable)

modulename: armada-370-xp.ko

configname: CONFIG_MACH_ARMADA_370_XP

Linux Kernel Configuration
└─>Marvell SOC with device tree
└─>MACH_ARMADA_370_XP
In linux kernel since version 3.1 (release Date: 2011-10-24)  
source code:
arch/arm/mach-mvebu/armada-370-xp.c