ROCm Runtime Support for respecting target xnack setting

This includes the changes provided by Konstantin, "Add xnack from elf header" (Change 136389).

Change-Id: I95e51141caa0d7c21903b09212c02e4906ec54a3

runtime/hsa-runtime/libamdhsacode/amd_elf_image.cpp

@@ -703,6 +703,7 @@ namespace amd {
 
       uint16_t Machine() override { return ehdr.e_machine; }
       uint16_t Type() override { return ehdr.e_type; }
+      uint32_t EFlags() override{ return ehdr.e_flags; }
 
       GElfStringTable* shstrtab() override;
       GElfStringTable* strtab() override;