arm64: kprobes: Use generic kretprobe trampoline handler

Use the generic kretprobe trampoline handler, and use
kernel_stack_pointer(regs) for framepointer verification.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870603544.1229682.10309733593594205725.stgit@devnote2