Add edac_mc_add_mc_with_groups() for initializing the mem_ctl_info
object with the optional attribute groups.  This allows drivers to
pass additional sysfs entries without manual (and racy)
device_create_file() and co calls.

edac_mc_add_mc() is kept as is, just calling edac_mc_add_with_groups()
with NULL groups.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: http://lkml.kernel.org/r/1423046938-18111-3-git-send-email-tiwai@suse.deSigned-off-by: Borislav Petkov <bp@suse.de>