samples/bpf: Fix build for task_fd_query_user.c

Add missing include for <linux/perf_event.h> which was removed from
perf-sys.h in commit 91854f9 ("perf tools: Move everything
related to sys_perf_event_open() to perf-sys.h").

Fixes: 91854f9 ("perf tools: Move everything related to sys_perf_event_open() to perf-sys.h")
Reported-by: KP Singh <[email protected]>
Reported-by: Florent Revest <[email protected]>
Signed-off-by: Björn Töpel <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Tested-by: KP Singh <[email protected]>
Acked-by: Song Liu <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

Author: Björn Töpel

samples/bpf/task_fd_query_user.c

@@ -13,6 +13,7 @@
 #include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <linux/perf_event.h>
 
 #include "libbpf.h"
 #include "bpf_load.h"