FindOpenMP: Add support for NVHPC compiler

Modules/FindOpenMP.cmake

@@ -117,6 +117,7 @@ function(_OPENMP_FLAG_CANDIDATES LANG)
     set(OMP_FLAG_PathScale "-openmp")
     set(OMP_FLAG_NAG "-openmp")
     set(OMP_FLAG_Absoft "-openmp")
+    set(OMP_FLAG_NVHPC "-mp")
     set(OMP_FLAG_PGI "-mp")
     set(OMP_FLAG_Flang "-fopenmp")
     set(OMP_FLAG_SunPro "-xopenmp")