SWDEV-425678 - Fix build failure in HIP samples

- Due to file reorg path changes cmake fails at find_package(hip) unless CMAKE_PREFIX_PATH is set explicitly
- Update CMakeLists.txt to set CMAKE_PREFIX_PATH
- Update Readme

Change-Id: Ibdb4419efcdd6583b059a728e48dfdb8f927a48b

samples/2_Cookbook/12_cmake_hip_add_executable/CMakeLists.txt

@@ -19,9 +19,11 @@
 # THE SOFTWARE.
 
 cmake_minimum_required(VERSION 3.10)
-if (NOT DEFINED ROCM_PATH )
-     set ( ROCM_PATH "/opt/rocm"  CACHE STRING "Default ROCM installation directory." )
-endif ()
+if(UNIX)
+  if(NOT DEFINED ROCM_PATH)
+    set(ROCM_PATH "/opt/rocm"  CACHE STRING "Default ROCM installation directory.")
+  endif()
+endif()
 
 if(NOT DEFINED HIP_PATH)
     if(NOT DEFINED ENV{HIP_PATH})
@@ -30,6 +32,9 @@ if(NOT DEFINED HIP_PATH)
         set(HIP_PATH $ENV{HIP_PATH} CACHE PATH "Path to which HIP has been installed")
     endif()
 endif()
+# Search for rocm in common locations
+list(APPEND CMAKE_PREFIX_PATH ${ROCM_PATH})
+
 set(CMAKE_MODULE_PATH "${HIP_PATH}/lib/cmake/hip/" ${CMAKE_MODULE_PATH})
 set(CMAKE_HIP_ARCHITECTURES OFF)
 project(12_cmake)