edac: struct device: replace bus_id with dev_name(), dev_set_name()

This patch is part of a larger patch series which will remove the "char
bus_id[20]" name string from struct device.  The device name is managed in
the kobject anyway, and without any size limitation, and just needlessly
copied into "struct device".

[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>