Add CMake support for PAL backend

Change-Id: Id0673d43217be305aa4ca7a612c416baee3fb23c


[ROCm/clr commit: da5f4c554e]

projects/clr/rocclr/platform/context.cpp

@@ -35,7 +35,7 @@
 #endif  //_WIN32
 
 #if (!defined(BUILD_HSA_TARGET) && defined(WITH_HSA_DEVICE) && \
-      defined(WITH_AMDGPU_PRO)) || defined(_WIN32) || defined(WITH_PAL_DEVICE)
+      defined(WITH_AMDGPU_PRO)) || defined(_WIN32)
 #define WITH_LIQUID_FLASH 1
 #endif