Convert CONFIG_FSL_MEMAC et al to Kconfig

This converts the following to Kconfig:
   CONFIG_FSL_MEMAC
   CONFIG_SYS_MEMAC_LITTLE_ENDIAN

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig b/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig
index 0c58a6d..5fb1346 100644
--- a/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig
+++ b/configs/ls2088ardb_tfa_SECURE_BOOT_defconfig
@@ -86,6 +86,8 @@
 CONFIG_PHYLIB=y
 CONFIG_PHY_AQUANTIA=y
 CONFIG_PHY_CORTINA=y
+CONFIG_FSL_MEMAC=y
+CONFIG_SYS_MEMAC_LITTLE_ENDIAN=y
 CONFIG_DM_ETH=y
 CONFIG_DM_MDIO=y
 CONFIG_E1000=y