net/i40e: add alarm handler
net/i40e: add alarm handler

This patch adds alarm handler, and then i40e
PF will use alarm handler instead of interrupt
handler when device is started and Rx interrupt
mode is disabled. This way will save CPU cycles
during receiving packets.

Signed-off-by: Beilei Xing <7fb7e49de6d75fb4140bfcdada52e66859d93ebd@intel.com>
Acked-by: Qi Zhang <9e9e58ffa71a29bb7b87766b362515be648fcbe0@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk