m25p80: Add debug message for no bdrv

If there is no backing bdrv, let the debugging developer know about it.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@gmail.com>

hw/block/m25p80.c

@@ -606,6 +606,7 @@ static int m25p80_init(SSISlave *ss)
             return 1;
         }
     } else {
+        DB_PRINT_L(0, "No BDRV - binding to RAM\n");
         memset(s->storage, 0xFF, s->size);
     }