[Libomptarget][FIX] Fix unintentinally used PUBLIC interface

Summary:
This was supposed to be private and caused some issues with certain
configs.
GitOrigin-RevId: 85af772f3b4067fce703b33cee0e2cdafc74a6d6
diff --git a/libomptarget/plugins-nextgen/CMakeLists.txt b/libomptarget/plugins-nextgen/CMakeLists.txt
index 8e8b040..c19fd80 100644
--- a/libomptarget/plugins-nextgen/CMakeLists.txt
+++ b/libomptarget/plugins-nextgen/CMakeLists.txt
@@ -47,7 +47,7 @@
   )
 
   llvm_update_compile_flags(${target_name})
-  target_link_libraries(${target_name} PUBLIC 
+  target_link_libraries(${target_name} PRIVATE
                         PluginCommon ${llvm_libs} ${OPENMP_PTHREAD_LIB})
 
   target_compile_definitions(${target_name} PRIVATE TARGET_NAME=${lib_name})