Convert CONFIG_TPL_NAND_INIT to Kconfig

This converts the following to Kconfig:
   CONFIG_TPL_NAND_INIT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
index 6ec3581..e3f6b90 100644
--- a/drivers/mtd/nand/raw/Makefile
+++ b/drivers/mtd/nand/raw/Makefile
@@ -16,7 +16,7 @@
 obj-$(CONFIG_SPL_NAND_ECC) += nand_ecc.o
 obj-$(CONFIG_SPL_NAND_BASE) += nand_base.o
 obj-$(CONFIG_SPL_NAND_IDENT) += nand_ids.o nand_timings.o
-obj-$(CONFIG_SPL_NAND_INIT) += nand.o
+obj-$(CONFIG_TPL_NAND_INIT) += nand.o
 ifeq ($(CONFIG_SPL_ENV_SUPPORT),y)
 obj-$(CONFIG_ENV_IS_IN_NAND) += nand_util.o
 endif