EDAC: Cleanup atomic_scrub mess

So first of all, this atomic_scrub() function's naming is bad. It looks
like an atomic_t helper. Change it to edac_atomic_scrub().

The bigger problem is that this function is arch-specific and every new
arch which doesn't necessarily need that functionality still needs to
define it, otherwise EDAC doesn't compile.

So instead of doing that and including arch-specific headers, have each
arch define an EDAC_ATOMIC_SCRUB symbol which can be used in edac_mc.c
for ifdeffery. Much cleaner.

And we already are doing this with another symbol - EDAC_SUPPORT. This
is also much cleaner than having CONFIG_EDAC enumerate all the arches
which need/have EDAC support and drivers.

This way I can kill the useless edac.h header in tile too.

Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-edac@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "Maciej W. Rozycki" <macro@codesourcery.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Steven J. Hill" <Steven.Hill@imgtec.com>
Cc: x86@kernel.org
Signed-off-by: Borislav Petkov <bp@suse.de>
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 2d2530c..a90e06a 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -2,15 +2,16 @@
 #	EDAC Kconfig
 #	Copyright (c) 2008 Doug Thompson www.softwarebitmaker.com
 #	Licensed and distributed under the GPL
-#
+
+config EDAC_ATOMIC_SCRUB
+	bool
 
 config EDAC_SUPPORT
 	bool
 
 menuconfig EDAC
 	bool "EDAC (Error Detection And Correction) reporting"
-	depends on HAS_IOMEM
-	depends on X86 || PPC || TILE || ARM || EDAC_SUPPORT
+	depends on HAS_IOMEM && EDAC_SUPPORT
 	help
 	  EDAC is designed to report errors in the core system.
 	  These are low-level errors that are reported in the CPU or