edac: add memory types strings for debugging

edac: add memory types strings for debugging

Instead of using deeply-nested conditionals for dumping the DIMM type in
debug mode, add a strings array of the supported DIMM types.

This is useful in cases where an edac driver supports multiple DRAM
types and is only defined in debug builds.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>