drivers: net: pfe_eth: LS1012A PFE driver introduction

This patch adds PFE driver to U-Boot

Following are the main driver files:-
pfe_hw.c: provides low level helper functions to initialize PFE
internal processor engines and other hardware blocks
pfe_driver.c: provides initialization functions
and packet send and receive functions
pfe_eth.c: provides high level gemac initialization functions
pfe_firmware.c: provides functions to load firmware into PFE
internal processor engines.
pfe_mdio.c: provides functions to initialize phy and mdio.

Signed-off-by: Calvin Johnson <calvin.johnson@nxp.com>
Signed-off-by: Anjaneyulu Jagarlmudi <anji.jagarlmudi@nxp.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>