EDAC, MCE: Rework MCE injection

Add sysfs injection facilities for testing of the MCE decoding code.
Remove large parts of amd64_edac_dbg.c, as a result, which did only
NB MCE injection anyway and the new injection code supports that
functionality already.

Add an injection module so that MCE decoding code in production kernels
like those in RHEL and SLES can be tested.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index 613b938..67d9ceb 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -486,7 +486,7 @@
 extern const char *htlink_msgs[8];
 
 #ifdef CONFIG_EDAC_DEBUG
-#define NUM_DBG_ATTRS 9
+#define NUM_DBG_ATTRS 5
 #else
 #define NUM_DBG_ATTRS 0
 #endif