Do not require OpenMP support for languages other than CXX

Specify CXX component when searching for OpenMP so that OpenMP support
is not required for other languages with CMake.

One caveat is that finding the OpenMP dependency downstream will require
CMake minimum version of 3.10

https://cmake.org/cmake/help/latest/module/FindOpenMP.html

Co-Authored-By: Luca Bertagna <lbertag@sandia.gov>

cmake/kokkos_tpls.cmake

@@ -103,13 +103,13 @@ if (Kokkos_ENABLE_IMPL_MDSPAN AND Kokkos_ENABLE_MDSPAN_EXTERNAL)
 endif()
 
 IF (Kokkos_ENABLE_OPENMP)
-  find_package(OpenMP REQUIRED)
+  find_package(OpenMP REQUIRED COMPONENTS CXX)
   # FIXME_TRILINOS Trilinos doesn't allow for Kokkos to use find_dependency
   # so we just append the flags here instead of linking with the OpenMP target.
   IF(KOKKOS_HAS_TRILINOS)
     COMPILER_SPECIFIC_FLAGS(DEFAULT ${OpenMP_CXX_FLAGS})
   ELSE()
-    KOKKOS_EXPORT_CMAKE_TPL(OpenMP REQUIRED)
+    KOKKOS_EXPORT_CMAKE_TPL(OpenMP REQUIRED COMPONENTS CXX)
   ENDIF()
 ENDIF()