perf lock contention: Fix a build error on 32-bit

It was reported that it failed to build the BPF lock contention skeleton
on 32 bit arch due to the size of long. The lost count is used only for
reporting errors due to lack of stackmap space through bad_hist which
type is 'int'. Let's use int type then.

Fixes: 6d499a6b3d90277d ("perf lock: Print the number of lost entries for BPF")
Reported-by: Jiri Slaby <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Song Liu <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

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

···
 int stack_skip;
 
 /* error stat */
-unsigned long lost;
+int lost;
 
 static inline int can_record(void)
 {

tools/perf/util/lock-contention.h

···
 	struct machine *machine;
 	struct hlist_head *result;
 	unsigned long map_nr_entries;
-	unsigned long lost;
+	int lost;
 	int max_stack;
 	int stack_skip;
 };