perf lock: Remove unused struct lock_contention_key

The struct lock_contention_key is never used, remove it.

Signed-off-by: Yuan Can <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/linux-perf-users/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/bpf_lock_contention.c

···
 
 static struct lock_contention_bpf *skel;
 
-/* should be same as bpf_skel/lock_contention.bpf.c */
-struct lock_contention_key {
-	s32 stack_id;
-};
-
 struct lock_contention_data {
 	u64 total_time;
 	u64 min_time;