Handle alternate_va==0

Have amd::MemoryRegion::Lock not assert if the alternate_va
is null but use the host_ptr instead because in the case where
the src/dst memory pointer is allocated via KFD, the host_ptr
is a GPUVA already.

Change-Id: If44368cc2854d4c0c477ae56e4eeabc37e54c1a5

runtime/hsa-runtime/core/runtime/amd_memory_region.cpp

@@ -542,9 +542,11 @@ hsa_status_t MemoryRegion::Lock(uint32_t num_agents, const hsa_agent_t* agents,
     uint64_t alternate_va = 0;
     if (MakeKfdMemoryResident(whitelist_nodes.size(), &whitelist_nodes[0],
                               host_ptr, size, &alternate_va, map_flag_)) {
-      assert(alternate_va != 0);
-      *agent_ptr = reinterpret_cast<void*>(alternate_va);
-
+      if (alternate_va != 0) {
+        *agent_ptr = reinterpret_cast<void*>(alternate_va);
+      } else {
+        *agent_ptr = host_ptr;
+      }
       for (core::Agent* gpu : whitelist_gpus) {
         reinterpret_cast<GpuAgentInt*>(gpu)->InitDma();
       }