cxgb4/cxgb4vf: Replace __skb_alloc_page with __dev_alloc_page

Drop the bloated use of __skb_alloc_page and replace it with
__dev_alloc_page.  In addition update the one other spot that is
allocating a page so that it allocates with the correct flags.

Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>