Convert CONFIG_SYS_LOADS_BAUD_CHANGE et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_LOADS_BAUD_CHANGE
   CONFIG_LOADS_ECHO

As part of this, we move CMD_SAVES to be after CMD_LOADS as they are
logically related (load or save an s-record format file) and this makes
grouping of CONFIG_SYS_LOADS_BAUD_CHANGE easier.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/MPC8548CDS_legacy_defconfig b/configs/MPC8548CDS_legacy_defconfig
index a5747c9..fe26296 100644
--- a/configs/MPC8548CDS_legacy_defconfig
+++ b/configs/MPC8548CDS_legacy_defconfig
@@ -28,6 +28,8 @@
 CONFIG_CMD_IMLS=y
 CONFIG_SYS_I2C_EEPROM_ADDR_LEN=2
 CONFIG_CMD_I2C=y
+CONFIG_LOADS_ECHO=y
+CONFIG_SYS_LOADS_BAUD_CHANGE=y
 CONFIG_CMD_PCI=y
 CONFIG_BOOTP_BOOTFILESIZE=y
 CONFIG_CMD_MII=y