Given we dont use anymore the struct net_device *dev argument, and this
interface brings litle benefit, remove netdev_{alloc|free}_page(), to
debloat include/linux/skbuff.h a bit.

(Some drivers used a mix of these interfaces and alloc_pages())

When allocating a page given to device for DMA transfer (device to
memory), it makes sense to use a cold one (__GFP_COLD)
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: Dimitris Michailidis <dm@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>