EDAC/dmc520: Assign the proper type to dimm->edac_mode

dimm->edac_mode contains values of type enum edac_type - not the
corresponding capability flags. Fix that.

Fixes: 1088750d

 ("EDAC: Add EDAC driver for DMC520")
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20210916085258.7544-1-bp@alien8.de