perf lock contention: Fix struct rq lock access

The BPF CO-RE's ignore suffix rule requires three underscores.
Otherwise it'd fail like below:

  $ sudo perf lock contention -ab
  libbpf: prog 'collect_lock_syms': BPF program load failed: Invalid argument
  libbpf: prog 'collect_lock_syms': -- BEGIN PROG LOAD LOG --
  reg type unsupported for arg#0 function collect_lock_syms#380
  ; int BPF_PROG(collect_lock_syms)
  0: (b7) r6 = 0                        ; R6_w=0
  1: (b7) r7 = 0                        ; R7_w=0
  2: (b7) r9 = 1                        ; R9_w=1
  3: <invalid CO-RE relocation>
  failed to resolve CO-RE relocation <byte_off> [381] struct rq__new.__lock (0:0 @ offset 0)

Fixes: 0c12284 ("perf lock contention: Support pre-5.14 kernels")
Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Hao Luo <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Song Liu <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: namhyung

tools/perf/util/bpf_skel/lock_contention.bpf.c

@@ -418,11 +418,11 @@ int contention_end(u64 *ctx)
 
 extern struct rq runqueues __ksym;
 
-struct rq__old {
+struct rq___old {
 	raw_spinlock_t lock;
 } __attribute__((preserve_access_index));
 
-struct rq__new {
+struct rq___new {
 	raw_spinlock_t __lock;
 } __attribute__((preserve_access_index));
 
@@ -434,8 +434,8 @@ int BPF_PROG(collect_lock_syms)
 
 	for (int i = 0; i < MAX_CPUS; i++) {
 		struct rq *rq = bpf_per_cpu_ptr(&runqueues, i);
-		struct rq__new *rq_new = (void *)rq;
-		struct rq__old *rq_old = (void *)rq;
+		struct rq___new *rq_new = (void *)rq;
+		struct rq___old *rq_old = (void *)rq;
 
 		if (rq == NULL)
 			break;