Initial HMM support

- Expose ROCclr interfaces for HIP usage
- ROCr interfaces aren't available in staging, thus control the
build with AMD_HMM_SUPPORT define

Change-Id: Iadc2bcc230e78d3b0dc22b235189c8cc80843446

rocclr/utils/flags.hpp

@@ -56,6 +56,8 @@ debug(size_t, PARAMETERS_MIN_ALIGNMENT, 16,                                   \
         "Minimum alignment required for the abstract parameters stack")       \
 debug(size_t, MEMOBJ_BASE_ADDR_ALIGN, 4*Ki,                                   \
         "Alignment of the base address of any allocate memory object")        \
+release(uint, ROC_HMM_FLAGS, 0,                                               \
+        "ROCm HMM configuration flags")                                       \
 release(cstring, GPU_DEVICE_ORDINAL, "",                                      \
         "Select the device ordinal (comma seperated list of available devices)") \
 release(bool, REMOTE_ALLOC, false,                                            \