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>

README

@@ -435,15 +435,6 @@ The following options need to be configured:
 		Define this variable to enable hw flow control in serial driver.
 		Current user of this option is drivers/serial/nsl16550.c driver
 
-- Serial Download Echo Mode:
-		CONFIG_LOADS_ECHO
-		If defined to 1, all characters received during a
-		serial download (using the "loads" command) are
-		echoed back. This might be needed by some terminal
-		emulations (like "cu"), but may as well just take
-		time on others. This setting #define's the initial
-		value of the "loads_echo" environment variable.
-
 - Removal of commands
 		If no commands are needed to boot, you can disable
 		CONFIG_CMDLINE to remove them. In this case, the command line
@@ -1455,9 +1446,6 @@ Configuration Settings:
 		the RAM base is not zero, or RAM is divided into banks,
 		this variable needs to be recalcuated to get the address.
 
-- CONFIG_SYS_LOADS_BAUD_CHANGE:
-		Enable temporary baudrate change while serial download
-
 - CONFIG_SYS_SDRAM_BASE:
 		Physical start address of SDRAM. _Must_ be 0 here.