[RFC] arm64: select FUNCTION_ALIGNMENT_16B

[Jisheng Zhang]

Hi,

Before arm64 explicitly selects FUNCTION_ALIGNMENT_4B or
FUNCTION_ALIGNMENT_8B if DYNAMIC_FTRACE_WITH_CALL_OPS, the compiler's
default function alignment is used. IIUC, gcc for aarch64 default
alignment is 16B when -O2, so to keep the same effect, do we need to
select FUNCTION_ALIGNMENT_16B instead?

Thanks