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/qemu-ppce500_defconfig b/configs/qemu-ppce500_defconfig
index 351913f..dd15b0e 100644
--- a/configs/qemu-ppce500_defconfig
+++ b/configs/qemu-ppce500_defconfig
@@ -24,6 +24,7 @@
 CONFIG_CMD_GREPENV=y
 CONFIG_CMD_DM=y
 CONFIG_CMD_GPIO=y
+CONFIG_LOADS_ECHO=y
 CONFIG_CMD_PCI=y
 CONFIG_CMD_POWEROFF=y
 CONFIG_CMD_DHCP=y