[flang][openacc] Allow constant variable in data clause (#71580)

The check introduced in #71444 was to restrictive and this patch relax
it so data clause can accept constant.

Author: clementval

flang/lib/Semantics/resolve-directives.cpp

@@ -1123,7 +1123,8 @@ void AccAttributeVisitor::AllowOnlyVariable(const parser::AccObject &object) {
       common::visitors{
           [&](const parser::Designator &designator) {
             const auto &name{GetLastName(designator)};
-            if (name.symbol && !semantics::IsVariableName(*name.symbol)) {
+            if (name.symbol && !semantics::IsVariableName(*name.symbol) &&
+                !semantics::IsNamedConstant(*name.symbol)) {
               context_.Say(designator.source,
                   "Only variables are allowed in data clauses on the %s "
                   "directive"_err_en_US,

flang/test/Semantics/OpenACC/acc-data.f90

@@ -210,4 +210,10 @@ subroutine sub4(t)
     !$acc data copy(t%t1_proc)
     !$acc end data
   end subroutine
+
+  subroutine sub5()
+    integer, parameter :: iparam = 1024
+    !$acc data copyin(iparam)
+    !$acc end data
+  end subroutine
 end module