Allow CPU cache info to be empty

Some new CPUs have different cache reporting structure causing thunk to
leave the cache information empty. Allow the cache information for CPU
agents to be empty as they are not used by language-runtimes

Change-Id: Ic5e880171ab20aa114b4b62bdb4479eb54066f7b

runtime/hsa-runtime/core/runtime/amd_cpu_agent.cpp

@@ -266,8 +266,6 @@ hsa_status_t CpuAgent::GetInfo(hsa_agent_info_t attribute, void* value) const {
       break;
     case HSA_AGENT_INFO_CACHE_SIZE: {
       std::memset(value, 0, sizeof(uint32_t) * 4);
-
-      assert(cache_props_.size() > 0 && "CPU cache info missing.");
       const size_t num_cache = cache_props_.size();
       for (size_t i = 0; i < num_cache; ++i) {
         const uint32_t line_level = cache_props_[i].CacheLevel;