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/edac_mc.c b/drivers/edac/edac_mc.c
index af3be19..943ed8c 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -30,11 +30,16 @@
 #include <linux/bitops.h>
 #include <asm/uaccess.h>
 #include <asm/page.h>
-#include <asm/edac.h>
 #include "edac_core.h"
 #include "edac_module.h"
 #include <ras/ras_event.h>
 
+#ifdef CONFIG_EDAC_ATOMIC_SCRUB
+#include <asm/edac.h>
+#else
+#define edac_atomic_scrub(va, size) do { } while (0)
+#endif
+
 /* lock to memory controller's control array */
 static DEFINE_MUTEX(mem_ctls_mutex);
 static LIST_HEAD(mc_devices);
@@ -874,7 +879,7 @@
 	virt_addr = kmap_atomic(pg);
 
 	/* Perform architecture specific atomic scrub operation */
-	atomic_scrub(virt_addr + offset, size);
+	edac_atomic_scrub(virt_addr + offset, size);
 
 	/* Unmap and complete */
 	kunmap_atomic(virt_addr);