net/ixgbe: enable 10Mb/s link setup for X553
net/ixgbe: enable 10Mb/s link setup for X553

This patch enable 10Mb/s link for ixgbe X553.
This new device has own device id of 0x15E4 and 0x15E5, so
ixgbe PMD driver need to special check when setup link for
these two types of device.

Signed-off-by: Wei Zhao <55941fd0e75edbdf274af2cfac8f147525678f08@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