ice: compress branches in ice_set_features()

Instead of rather verbose comparison of current netdev->features bits vs
the incoming ones from user, let us compress them by a helper features
set that will be the result of netdev->features XOR features. This way,
current, extensive branches:

	if (features & NETIF_F_BIT && !(netdev->features & NETIF_F_BIT))
		set_feature(true);
	else if (!(features & NETIF_F_BIT) && netdev->features & NETIF_F_BIT)
		set_feature(false);

can become:

	netdev_features_t changed = netdev->features ^ features;

	if (changed & NETIF_F_BIT)
		set_feature(!!(features & NETIF_F_BIT));

This is nothing new as currently several other drivers use this
approach, which I find much more convenient.

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>