patch 8.2.1990: cursor position wrong in terminal popup with finished job

Problem:    Cursor position wrong in terminal popup with finished job.
Solution:   Only add the top and left offset when not done already.
            (closes #7298)
diff --git a/src/terminal.c b/src/terminal.c
index 7f38bf7..6be7579 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -2208,7 +2208,10 @@
     {
 	wp->w_wrow += popup_top_extra(curwin);
 	wp->w_wcol += popup_left_extra(curwin);
+	wp->w_flags |= WFLAG_WCOL_OFF_ADDED | WFLAG_WROW_OFF_ADDED;
     }
+    else
+	wp->w_flags &= ~(WFLAG_WCOL_OFF_ADDED | WFLAG_WROW_OFF_ADDED);
 #endif
     wp->w_valid |= (VALID_WCOL|VALID_WROW);
 }