selftests/bpf: Remove not used headers

The following three uapi headers:

    tools/arch/arm64/include/uapi/asm/bpf_perf_event.h
    tools/arch/s390/include/uapi/asm/bpf_perf_event.h
    tools/arch/s390/include/uapi/asm/ptrace.h

were introduced in commit 618e165b ("selftests/bpf: sync kernel headers
and introduce arch support in Makefile"), they are not used any more after
commit 720f228e ("bpf: fix broken BPF selftest build"), so remove them.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/1676533861-27508-1-git-send-email-yangtiezhu@loongson.cnSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/arch/arm64/include/uapi/asm/bpf_perf_event.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _UAPI__ASM_BPF_PERF_EVENT_H__
-#define _UAPI__ASM_BPF_PERF_EVENT_H__
-
-#include <asm/ptrace.h>
-
-typedef struct user_pt_regs bpf_user_pt_regs_t;
-
-#endif /* _UAPI__ASM_BPF_PERF_EVENT_H__ */

tools/arch/s390/include/uapi/asm/bpf_perf_event.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _UAPI__ASM_BPF_PERF_EVENT_H__
-#define _UAPI__ASM_BPF_PERF_EVENT_H__
-
-#include "ptrace.h"
-
-typedef user_pt_regs bpf_user_pt_regs_t;
-
-#endif /* _UAPI__ASM_BPF_PERF_EVENT_H__ */