CONFIG_MACH_ARMADA_370 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Marvell Armada 370 boards

configname: CONFIG_MACH_ARMADA_370

Linux Kernel Configuration
└─>Marvell SOC with device tree
└─>Marvell Armada 370 boards
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Say 'Y' here if you want your kernel to support boards based
on the Marvell Armada 370 SoC with device tree.