net: fclone allocation small optimization

net: fclone allocation small optimization

After skb allocation, initial skb->fclone value is 0 (SKB_FCLONE_UNAVAILABLE)

We can replace one RMW sequence with a single OR instruction.

	movzbl 0x7e(%r13),%eax // skb->fclone = SKB_FCLONE_ORIG;
	and    $0xf3,%al
	or     $0x4,%al
	mov    %al,0x7e(%r13)
->
	or     $0x4,0x7e(%r13) // skb->fclone |= SKB_FCLONE_ORIG;

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260116164402.1872649-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>