sim-se: small performance optimization

A local variable was being set inside a loop when it should
have been set outside the loop. This changeset moves the
variable to the appropriate place.

Change-Id: If7655b501bd819c39d35dea4c316b4b9ed3173a2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17108
Maintainer: Brandon Potter <Brandon.Potter@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

src/sim/process.cc

@@ -199,8 +199,8 @@ Process::clone(ThreadContext *otc, ThreadContext *ntc,
          * host file descriptors are also dup'd so that the flags for the
          * host file descriptor is independent of the other process.
          */
+        std::shared_ptr<FDArray> nfds = np->fds;
         for (int tgt_fd = 0; tgt_fd < fds->getSize(); tgt_fd++) {
-            std::shared_ptr<FDArray> nfds = np->fds;
             std::shared_ptr<FDEntry> this_fde = (*fds)[tgt_fd];
             if (!this_fde) {
                 nfds->setFDEntry(tgt_fd, nullptr);