ethernet/realtek: use napi_alloc_skb instead of netdev_alloc_skb_ip_align

This replaces most of the calls to netdev_alloc_skb_ip_align in the Realtek
drivers.  The one instance I didn't replace in 8139cp.c is because it was
called as a part of init and as such is not always accessed from the
softirq context.

Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>