Convert CONFIG_CMD_SATA to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_SATA

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/MPC837XERDB_defconfig b/configs/MPC837XERDB_defconfig
index 2f3e7b0..fc21671 100644
--- a/configs/MPC837XERDB_defconfig
+++ b/configs/MPC837XERDB_defconfig
@@ -8,6 +8,7 @@
 CONFIG_CMD_MMC=y
 CONFIG_CMD_I2C=y
 CONFIG_CMD_USB=y
+CONFIG_CMD_SATA=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y