drivers/edac: add mips and ppc visibility

1) Remove an old CVS ID string

2) change EDAC from a tristate option to a simple bool option

3) In addition to the X86 arch, PPC and MIPS also have drivers in the
submission queue.  This patch turns on the EDAC flag for those archs.  Each
driver will have its respective 'depends on ARCH' set.

Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>