CONFIG_CPU_LOONGSON2F is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

Loongson 2F

configname: CONFIG_CPU_LOONGSON2F

CPU type
└─>Loongson 2F
In linux kernel since version 2.6.33 (release Date: 2010-02-24)  
The Loongson 2F processor implements the MIPS III instruction set
with many extensions.

Loongson2F have built-in DDR2 and PCIX controller. The PCIX controller
have a similar programming interface with FPGA northbridge used in
Loongson2E.