menuconfig: Get rid of the top-level entries for "Load an Alternate/Save an Alternate"

Now we have Load/Save buttons to do the Load/Save
in the convenient place, so we can drop the
top-level entries.

Signed-off-by: Wang YanQing <udknight@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>