SWDEV-402093 - Updated README to use AMDGPU_TARGETS=native to enable compiler autodetection (#378)

Change-Id: I33a71d12b5b883eacac706725322bc13e0d57852

[ROCm/hip-tests commit: 30fcf2f17c]

projects/hip-tests/samples/2_Cookbook/18_cmake_hip_device/README.md

@@ -12,7 +12,11 @@ Note, users may need to add ADMGPU support as command line option, if test faile
 ```
 CXX="$(hipconfig -l)"/clang++ cmake -DCMAKE_PREFIX_PATH=/opt/rocm -DAMDGPU_TARGETS="gfx1102" ..
 ```
-
+To enable compiler auto detection of gpu users may need to add ADMGPU support as command line option, 
+if test failed to run, for example,
+```
+CXX="$(hipconfig -l)"/clang++ cmake -DCMAKE_PREFIX_PATH=/opt/rocm -DAMDGPU_TARGETS=native ..
+```
 II. Test
 
 ```

projects/hip-tests/samples/2_Cookbook/19_cmake_lang/README.md

@@ -19,6 +19,11 @@ Note, users may need to add AMD GPU support, if test failed, for example,
 ```
 CXX="$(hipconfig -l)"/clang++ FC=$(which gfortran) cmake -DCMAKE_PREFIX_PATH=/opt/rocm -DAMDGPU_TARGETS="gfx1102" ..
 ```
+To enable compiler auto detection of gpu users may need to add ADMGPU support as command line option, 
+if test failed to run, for example,
+```
+CXX="$(hipconfig -l)"/clang++ FC=$(which gfortran) cmake -DCMAKE_PREFIX_PATH=/opt/rocm -DAMDGPU_TARGETS=native ..
+```
 III. Test
 ```
 ./test_fortran

projects/hip-tests/samples/2_Cookbook/21_cmake_hip_cxx_clang/README.md

@@ -7,7 +7,11 @@ rm -rf *;
 CXX="$(hipconfig -l)"/amdclang++ cmake -DCMAKE_PREFIX_PATH=/opt/rocm ..
 make
 ```
-
+To enable compiler auto detection of gpu users may need to add ADMGPU support as command line option, 
+if test failed to run, for example,
+```
+CXX="$(hipconfig -l)"/amdclang++ cmake -DCMAKE_PREFIX_PATH=/opt/rocm -DAMDGPU_TARGETS=native ..
+```
 II. Test
 
 ```