amd64_edac: Carve out ECC-related hw settings

This is in preparation for the init path reorganization where we want
only to

1) test whether a particular node supports ECC
2) can it be enabled

and only then do the necessary allocation/initialization. For that,
we need to decouple the ECC settings of the node from the instance's
descriptor.

The should be no functional change introduced by this patch.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index 4bc6f18..b76dce9 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -461,17 +461,21 @@
 	/* place to store error injection parameters prior to issue */
 	struct error_injection injection;
 
-	/* Save old hw registers' values before we modified them */
-	u32 nbctl_mcgctl_saved;		/* When true, following 2 are valid */
-	u32 old_nbctl;
-
 	/* DCT per-family scrubrate setting */
 	u32 min_scrubrate;
 
 	/* family name this instance is running on */
 	const char *ctl_name;
 
-	/* misc settings */
+};
+
+/*
+ * per-node ECC settings descriptor
+ */
+struct ecc_settings {
+	u32 old_nbctl;
+	bool nbctl_valid;
+
 	struct flags {
 		unsigned long nb_mce_enable:1;
 		unsigned long nb_ecc_prev:1;