bpf: Forces __buildin_memcmp not to generate a call upto 1024 bytes.

bpf: Forces __buildin_memcmp not to generate a call upto 1024 bytes.

This patch forces __builtin_memcmp calls upto data sizes of 1024 to
become inline in caller.
This is a requirement by BPF and it mimics the default behaviour of the
clang BPF implementation.

gcc/ChangeLog:
	* config/bpf/bpf.cc (bpf_use_by_pieces_infrastructure_p): Added
	function to bypass default behaviour.
	* config/bpf/bpf.h (COMPARE_MAX_PIECES): Defined to 1024 bytes.