SWDEV-436821 Update hip samples Readme files

Change-Id: I6bf3a72eac4a4242cb2dbf4e6eee73e0e1bef2ef


[ROCm/hip-tests commit: 76dd8ea569]

projects/hip-tests/samples/2_Cookbook/14_gpu_arch/Readme.md

@@ -0,0 +1,15 @@
+# gpu_arch
+
+- Build the sample using cmake
+```
+$ mkdir build; cd build
+$ cmake .. -DCMAKE_PREFIX_PATH=/opt/rocm
+$ make
+```
+- Execute the sample
+```
+$ ./gpuarch
+success
+```
+
+## Note : This sample works on architectures gfx908 and above