Add Ethernet support for STM32MP13.
STM32MP13 is STM32 SOC with 2 GMACs instances.
GMAC IP version is SNPS 4.20.
GMAC IP configure with 1 RX and 1 TX queue.
DMA HW capability register supported
RX Checksum Offload Engine supported
TX Checksum insertion supported
Wake-Up On Lan supported
TSO supported
Signed-off-by: Christophe Roullier <christophe.roullier@xxxxxxxxxxx>