mm: function to get the mode of a range of memory.

This supersedes mm_vm_is_mapped() since that is checking that the range
was not mapped with MM_MODE_INVALID.

Change-Id: Ic3d5018a6d207d092a7f6bf853b015eba22945bb
diff --git a/inc/hf/arch/mm.h b/inc/hf/arch/mm.h
index fea5f65..d6c8211 100644
--- a/inc/hf/arch/mm.h
+++ b/inc/hf/arch/mm.h
@@ -134,6 +134,11 @@
 uint64_t arch_mm_mode_to_attrs(int mode);
 
 /**
+ * Converts the stage-2 block attributes back to the corresponding mode.
+ */
+int arch_mm_stage2_attrs_to_mode(uint64_t attrs);
+
+/**
  * Initializes the arch specific memory management state.
  */
 bool arch_mm_init(paddr_t table, bool first);