It's preparation for future use. At this moment, the RGMII port is used
only for a connection to the MAC interface, but in the future, someone
could connect a PHY to it. Using the "phy_interface_mode_is_rgmii" macro
allows for the proper recognition of all RGMII modes.
Suggested-by: Russell King <linux@xxxxxxxxxxxxxxx>
Signed-off-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>