ixgbe/base: move X550 MDIO clock speed init
ixgbe/base: move X550 MDIO clock speed init

The x550 MDIO clock speed must be configured prior to first MDIO read or
write. The default MDIO clock speed is not valid, therefore the driver
is configuring a valid speed prior to reading the copper PHY device id.

Signed-off-by: Wenzhuo Lu <58cb9036bdff9a5412edc3b9f70e105ccf59954f@intel.com>

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