EDAC, mellanox: Add ECC support for BlueField DDR4

Add ECC support for Mellanox BlueField SoC DDR controller.
This requires SMC to the running Arm Trusted Firmware to report
what is the current memory configuration.

Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Shravan Kumar Ramani <sramani@mellanox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>