enic: remove #ifdef CONFIG_RFS_ACCEL around filter structures

This patch removes the #ifdef CONFIG_RFS_ACCEL around the classifier filter
structures. This makes the filter structures available when CONFIG_RFS_ACCEL = n.

Introduce enic_rfs_timer_start() & enic_rfs_timer_stop() to start/stop the
timer. These two functions are nop when CONFIG_RFS_ACCEL = n.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>