bpf_net_helpers - add definition for bpf_skb_change_head

Based on kernel's //include/uapi/linux/bpf.h:
   * int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)

Test: builds
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I1d378d35a9bce654ebd3d03d96c364f3b0c3e22d
1 file changed