Add extra offsets where promise metadata can be found.

Author: Luke Yelavich <themuso@ubuntu.com>

--- a/lib/format/ataraid/pdc.h
+++ b/lib/format/ataraid/pdc.h
@@ -13,7 +13,7 @@
 
 #include <stdint.h>
 
-#define PDC_CONFIGOFFSETS	63,255,256,16,399,591,675,735,974,991
+#define PDC_CONFIGOFFSETS	63,255,256,16,399,591,675,735,974,991,911,951
 #define	PDC_DATAOFFSET 0
 
 /*