workqueue: do not rely on function object

With CTF debuginfo, for certain versions of UEK, there are no type
signatures for functions. This means that Objects cannot be constructed
for those functions, and thus using prog["function_name"] will not work.
However, the symbols are still present, and thus
prog.symbol("function_name") will be equivalent.

Remove the usage here for delayed_work_timer_fn().

Orabug: 37695749

Signed-off-by: Stephen Brennan <[email protected]>

Author: brenns10

drgn_tools/workqueue.py

@@ -651,8 +651,8 @@ def show_unexpired_delayed_works(
                         "entry",
                     ):
                         if (
-                            prog["delayed_work_timer_fn"].address_of_()
-                            == timer.function
+                            prog.symbol("delayed_work_timer_fn").address
+                            == timer.function.value_()
                         ):
                             dwork = container_of(
                                 timer,