[libc][amdgpu] Tolerate different install directories for hsa.h

HSA headers might be under a hsa/ directory or might not.
This scheme matches the one used by the openmp amdgpu plugin.

Reviewed By: jhuber6, jplehr

Differential Revision: https://reviews.llvm.org/D155812

libc/utils/gpu/loader/amdgpu/Loader.cpp

@@ -15,8 +15,18 @@
 
 #include "Loader.h"
 
-#include <hsa/hsa.h>
-#include <hsa/hsa_ext_amd.h>
+#if defined(__has_include)
+#if __has_include("hsa/hsa.h")
+#include "hsa/hsa.h"
+#include "hsa/hsa_ext_amd.h"
+#elif __has_include("hsa.h")
+#include "hsa.h"
+#include "hsa_ext_amd.h"
+#endif
+#else
+#include "hsa/hsa.h"
+#include "hsa/hsa_ext_amd.h"
+#endif
 
 #include <cstdio>
 #include <cstdlib>