Convert CONFIG_SYS_CORTINA_FW_IN_MMC et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_CORTINA_FW_IN_MMC
   CONFIG_SYS_CORTINA_FW_IN_NAND
   CONFIG_SYS_CORTINA_FW_IN_NOR
   CONFIG_SYS_CORTINA_FW_IN_REMOTE
   CONFIG_SYS_CORTINA_FW_IN_SPIFLASH

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/T2080RDB_NAND_defconfig b/configs/T2080RDB_NAND_defconfig
index bed4fed..8c6a8e1 100644
--- a/configs/T2080RDB_NAND_defconfig
+++ b/configs/T2080RDB_NAND_defconfig
@@ -63,6 +63,7 @@
 CONFIG_PHYLIB=y
 CONFIG_PHY_AQUANTIA=y
 CONFIG_PHY_CORTINA=y
+CONFIG_SYS_CORTINA_FW_IN_NAND=y
 CONFIG_E1000=y
 CONFIG_FMAN_ENET=y
 CONFIG_MII=y