drivers/edac: add dev_name getter function

Move dev_name() macro to a more generic interface since it's not possible
to determine whether a device is pci, platform, or of_device easily.

Now each low level driver sets the name into the control structure, and
the EDAC core references the control structure for the information.

Better abstraction.

Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>