ftrace: Fix softlockup in ftrace_module_enable

In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix softlockup in ftrace_module_enable A soft lockup was observed when loading amdgpu module. If a module has a lot of tracable functions, multiple calls to kallsyms_lookup can spend too much time in RCU critical section and with disabled preemption, causing kernel panic. This is the same issue that was fixed in commit d0b24b4e91fc ("ftrace: Prevent RCU stall on PREEMPT_VOLUNTARY kernels") and commit 42ea22e754ba ("ftrace: Add cond_resched() to ftrace_graph_set_hash()"). Fix it the same way by adding cond_resched() in ftrace_module_enable.