tcp: remove some holes in struct tcp_sock

tcp: remove some holes in struct tcp_sock

By moving some fields around, this patch shrinks
holes size from 56 to 32, saving 24 bytes on 64bit arches.

After the patch pahole gives the following for 'struct tcp_sock':

	/* size: 2304, cachelines: 36, members: 162 */
	/* sum members: 2234, holes: 6, sum holes: 32 */
	/* sum bitfield members: 34 bits, bit holes: 5, sum bit holes: 14 bits */
	/* padding: 32 */
	/* paddings: 3, sum paddings: 10 */
	/* forced alignments: 1, forced holes: 1, sum forced holes: 12 */

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240227192721.3558982-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>