Convert CONFIG_MCFUART to Kconfig

This converts the following to Kconfig:
	CONFIG_MCFUART

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/M5249EVB_defconfig b/configs/M5249EVB_defconfig
index d2ac18e..77eedd6 100644
--- a/configs/M5249EVB_defconfig
+++ b/configs/M5249EVB_defconfig
@@ -23,3 +23,4 @@
 CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_SYS_FLASH_PROTECTION=y
 CONFIG_SYS_FLASH_CFI=y
+CONFIG_MCFUART=y