bpf: Revert bpf_overrid_function() helper changes.

arch/Kconfig

arch/x86/Kconfig

arch/x86/include/asm/kprobes.h

arch/x86/include/asm/ptrace.h

arch/x86/kernel/kprobes/ftrace.c

include/linux/filter.h

include/linux/trace_events.h

include/uapi/linux/bpf.h

kernel/bpf/core.c

kernel/bpf/verifier.c

kernel/events/core.c

kernel/trace/Kconfig

kernel/trace/bpf_trace.c

kernel/trace/trace_kprobe.c

kernel/trace/trace_probe.h

samples/bpf/Makefile

samples/bpf/test_override_return.sh

samples/bpf/tracex7_kern.c

samples/bpf/tracex7_user.c

tools/include/uapi/linux/bpf.h