EDAC/npcm: Add NPCM memory controller driver

Add driver for memory controller present on Nuvoton NPCM SoCs. The
memory controller supports single bit error correction and double bit
error detection.

Signed-off-by: Marvin Lin <milkfafa@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230111093245.318745-4-milkfafa@gmail.com