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/omap3_overo_defconfig b/configs/omap3_overo_defconfig
index 20542e9..5d1cbe9 100644
--- a/configs/omap3_overo_defconfig
+++ b/configs/omap3_overo_defconfig
@@ -50,4 +50,5 @@
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
 CONFIG_FAT_WRITE=y
+CONFIG_BCH=y
 CONFIG_OF_LIBFDT=y