Convert CONFIG_CMD_SAVES to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_SAVES

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index d623a43..9efc2cf 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -779,6 +779,12 @@
 	  Attachment, where AT refers to an IBM AT (Advanced Technology)
 	  computer released in 1984.
 
+config CMD_SAVES
+	bool "saves - Save a file over serial in S-Record format"
+	help
+	  Provides a way to save a binary file using the Motorola S-Record
+	  format over the serial line.
+
 config CMD_SF
 	bool "sf"
 	help