qede: Optimize aggregation information size

Driver needs to maintain a structure per-each concurrent possible
open aggregation, but the structure storing that metadata is far from
being optimized - biggest waste in it is that there are 2 buffer metadata,
one for a replacement buffer when the aggregation begins and the other for
holding the first aggregation's buffer after it begins [as firmware might
still update it]. Those 2 can safely be united into a single metadata
structure.

struct qede_agg_info changes the following:

	/* size: 120, cachelines: 2, members: 9 */
	/* sum members: 114, holes: 1, sum holes: 4 */
	/* padding: 2 */
	/* paddings: 2, sum paddings: 8 */
	/* last cacheline: 56 bytes */
 -->
	/* size: 48, cachelines: 1, members: 9 */
	/* paddings: 1, sum paddings: 4 */
	/* last cacheline: 48 bytes */

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>