edac: Fix printf-style formatting in slog call (#3759)

The Debug call added in #3734 passes printf verbs and positional arguments to
slog, which does not format them. The format string is logged verbatim and the
arguments are consumed as key/value pairs, so controller and channel numbers
become attribute keys: a duplicate key when the two are equal, and otherwise a
key whose name changes on every iteration. Under --log.format=json that is an
object with a repeated key, and parsers silently drop one of the values. The
csrow number and the error, the two things worth reading, are the only parts
that survive, and they appear as values of meaningless keys.

%w compounds it: that is an fmt.Errorf directive and not a valid Printf verb,
left behind when the error return this replaced was converted to a log line.

Pass the values as named attributes instead. Metric output is unchanged.

Signed-off-by: Adam Butler <github@at-blacknight.com>