MIPS: Loongson: Add Loongson-3 Kconfig options

MIPS: Loongson: Add Loongson-3 Kconfig options

Added Kconfig options include: Loongson-3 CPU and machine definition,
CPU cache features, UEFI-like firmware interface (LEFI), HT-linked PCI,
and swiotlb support.

Signed-off-by: Huacai Chen <[email protected]>
Signed-off-by: Hongliang Tao <[email protected]>
Signed-off-by: Hua Yan <[email protected]>
Tested-by: Alex Smith <[email protected]>
Reviewed-by: Alex Smith <[email protected]>
Cc: John Crispin <[email protected]>
Cc: Steven J. Hill <[email protected]>
Cc: Aurelien Jarno <[email protected]>
Cc: [email protected]
Cc: Fuxin Zhang <[email protected]>
Cc: Zhangjin Wu <[email protected]>
Patchwork: https://patchwork.linux-mips.org/patch/6637
Signed-off-by: Ralf Baechle <[email protected]>