[OpenMP][OMPIRBuilder] Remove redundant initialization of IsTargetDevice

This property of the `OpenMPIRBuilderConfig` is already initialized in the
constructor for `OMPInformationCache`. This looks to be a leftover after a
merge from main (comment [here](llvm#67000 (comment))).

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

@@ -549,7 +549,6 @@ struct OMPInformationCache : public InformationCache {
   void recollectUses() {
     for (int Idx = 0; Idx < RFIs.size(); ++Idx)
       recollectUsesForFunction(static_cast<RuntimeFunction>(Idx));
-    OMPBuilder.Config.IsTargetDevice = isOpenMPDevice(OMPBuilder.M);
   }
 
   // Helper function to inherit the calling convention of the function callee.