Convert CONFIG_BCH to Kconfig

This converts the following to Kconfig:
   CONFIG_BCH

Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/kmcoge5ne_defconfig b/configs/kmcoge5ne_defconfig
index 4f38ea1..5165496 100644
--- a/configs/kmcoge5ne_defconfig
+++ b/configs/kmcoge5ne_defconfig
@@ -24,4 +24,5 @@
 CONFIG_MTD_NOR_FLASH=y
 # CONFIG_PCI is not set
 CONFIG_SYS_NS16550=y
+CONFIG_BCH=y
 CONFIG_OF_LIBFDT=y