lttng-modules: fix build against 5.18-rc7+

lttng-modules: fix build against 5.18-rc7+

lttng-modules fails to build against 5.18-rc7, the details of the fix
are as follows:

   The commit [fix: sched/tracing: Don't re-read p->state when emitting
   sched_switch event (v5.18)] was correct, but the kernel changed their
   mind with the following commit:

      commit 9c2136be0878c88c53dea26943ce40bb03ad8d8d
      Author: Delyan Kratunov <delyank@fb.com>
      Date:   Wed May 11 18:28:36 2022 +0000

          sched/tracing: Append prev_state to tp args instead

          Commit fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting
          sched_switch event, 2022-01-20) added a new prev_state argument to the
          sched_switch tracepoint, before the prev task_struct pointer.

          This reordering of arguments broke BPF programs that use the raw
          tracepoint (e.g. tp_btf programs). The type of the second argument has
          changed and existing programs that assume a task_struct* argument
          (e.g. for bpf_task_storage access) will now fail to verify.

          If we instead append the new argument to the end, all existing programs
          would continue to work and can conditionally extract the prev_state
          argument on supported kernel versions.

          Fixes: fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20)
          Signed-off-by: Delyan Kratunov <delyank@fb.com>
          Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
          Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
   By reordering the parameters (again) we can get back up and building.

Upstream-Status: Backport

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>