amd64_edac: Cleanup return type of amd64_determine_edac_cap()

Sparse complains that edac_cap was declared as dev_type and we are
returning edac_type.  Historically, edac_type was correct but since
then we have changed it to return a bit field.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20111006063025.GA2615@mwanda
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>