sunxi: gmac: Update bananapi fixup to the new CONFIG_TARGET_<BOARD> structure

The magic bit toucher needs to be updated to reflect the new board Kconfig structure

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>