skbuff: make __skb_header_pointer()'s data argument const

The function never modifies the input buffer, so 'data' argument
can be marked as const.
This implies one harmless cast-away.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Lobakin 2021-03-14 11:11:14 +00:00 • committed by David S. Miller
commit e3305138da