netdevice.h: Change netif_<level> macros to call netdev_<level> functions

Reduces text ~300 bytes of text (woohoo!) in an x86 defconfig

$ size vmlinux*
   text	   data	    bss	    dec	    hex	filename
7198526	 720112	1366288	9284926	 8dad3e	vmlinux
7198862	 720112	1366288	9285262	 8dae8e	vmlinux.netdev

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>