Convert CONFIG_TEGRA_NAND to Kconfig

This converts the following to Kconfig:
   CONFIG_TEGRA_NAND

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/seaboard_defconfig b/configs/seaboard_defconfig
index bff7a04..f3d3b0a 100644
--- a/configs/seaboard_defconfig
+++ b/configs/seaboard_defconfig
@@ -18,7 +18,6 @@
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_I2C=y
 CONFIG_CMD_MMC=y
-CONFIG_CMD_NAND=y
 CONFIG_CMD_USB=y
 # CONFIG_CMD_SETEXPR is not set
 # CONFIG_CMD_NFS is not set
@@ -36,6 +35,7 @@
 CONFIG_TEGRA_KEYBOARD=y
 CONFIG_MTD=y
 CONFIG_MTD_RAW_NAND=y
+CONFIG_TEGRA_NAND=y
 CONFIG_SYS_NAND_ONFI_DETECTION=y
 CONFIG_DM_PMIC=y
 CONFIG_DM_REGULATOR=y