EDAC/synopsys: Fix wrong value type assignment for edac_mode

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

Issue caught by Coverity check "enumerated type mixed with another
type."

 [ bp: Rewrite commit message, add tags. ]

Fixes: ae9b56e3

 ("EDAC, synps: Add EDAC support for zynq ddr ecc controller")
Signed-off-by: Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri@xilinx.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20210818072315.15149-1-shubhrajyoti.datta@xilinx.com