Revert "[libomptarget] Build amdgcn devicertl by default"

This reverts commit e23f3502d9a2b1e9abd445130a22cc00f6464da8.
It broke the build of openmp for clang built without amdgcn
support. D98746, under review, would allow this to reland.

GitOrigin-RevId: dbf8f2b089e842d445442a25a0aee78e3b3b500d
diff --git a/libomptarget/deviceRTLs/CMakeLists.txt b/libomptarget/deviceRTLs/CMakeLists.txt
index 8bbf987..3df94ea 100644
--- a/libomptarget/deviceRTLs/CMakeLists.txt
+++ b/libomptarget/deviceRTLs/CMakeLists.txt
@@ -10,5 +10,4 @@
 #
 ##===----------------------------------------------------------------------===##
 
-add_subdirectory(amdgcn)
 add_subdirectory(nvptx)
diff --git a/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt b/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt
index 361e052..8ba0572 100644
--- a/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt
+++ b/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt
@@ -154,6 +154,6 @@
   add_custom_target(lib${libname}-${mcpu} ALL DEPENDS ${bc_libname})
 
   install(FILES ${OUTPUTDIR}/${bc_libname}
-     DESTINATION "${OPENMP_INSTALL_LIBDIR}"
+     DESTINATION "${OPENMP_INSTALL_LIBDIR}/libdevice"
   )
 endforeach()