EDAC: Test correct variable in ->store function

commit 8024c4c0 upstream.

We're testing for ->show but calling ->store().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>