net: fix IFF_TX_SKB_NO_LINEAR definition

The "1<<31" shift has a sign extension bug so IFF_TX_SKB_NO_LINEAR is
0xffffffff80000000 instead of 0x0000000080000000.

Fixes: c2ff53d8 ("net: Add priv_flags for allow tx skb without linear")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Link: https://lore.kernel.org/r/YrRrcGttfEVnf85Q@kili


Signed-off-by: Jakub Kicinski <kuba@kernel.org>