Update comment for new buffer location property in aocl_mmd.h

Author: bsyrowik

include/MMD/aocl_mmd.h

@@ -489,6 +489,9 @@ typedef enum {
    *  Specifies the buffer location used for USM API calls.  The buffer location
    *  is an integer index that corresponds to a global memory location in the
    *  board_spec.xml file.  Similar to AOCL_MMD_MEM_PROPERTIES_GLOBAL_MEMORY.
+   *  The buffer location value may not have been validated by the OpenCL
+   *  runtime, so it is the responsibility of the MMD layer to ensure the value
+   *  is valid.
    */
   AOCL_MMD_MEM_PROPERTIES_BUFFER_LOCATION
 } aocl_mmd_mem_properties_t;