EDAC: Add an EDAC driver for the Loongson memory controller

EDAC: Add an EDAC driver for the Loongson memory controller

Add ECC support for Loongson SoC DDR controller. This driver reports single
bit errors (CE) only.

Only ACPI firmware is supported.

  [ bp: Document what last_ce_count is for. ]

Signed-off-by: Zhao Qunqin <zhaoqunqin@loongson.cn>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/20241219124846.1876-1-zhaoqunqin@loongson.cn
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>