Add support for loongarch cpu

[zhuyaliang]

Add loongarch support, the new architecture launched by China's Loongson. It can be compiled and run normally under loongarch architecture. loongarch cpuinfo

[zhuyaliang]

@wfeldt Please review the code

[sdlaqz]

Test passed

[wangjingwb]

@wfeldt Can be compiled and used normally on the loongarch architecture

./hwinfo --cpu --short 
cpu:                                                            
 Loongson-3C5000, 2200 MHz
 Loongson-3C5000, 2200 MHz
 Loongson-3C5000, 2200 MHz
 Loongson-3C5000, 2200 MHz
 Loongson-3C5000, 2200 MHz
 Loongson-3C5000, 2200 MHz

/hwinfo --arch
Arch: LoongArch/grub      

[cnmushiba]

Test OK