config: move down companion libraries sub-menu

Move the companion libraries sub-menu down the main menu.
That way, the user does not need to go back and forth in the menu
to change options set by the different components that select the
companion libraries (binutils, gcc, gdb).

# ia64 specific config options

# depends on EXPERIMENTAL

config ARCH_ia64

    select ARCH_USE_MMU

    select ARCH_64

    select ARCH_SUPPORTS_BOTH_ENDIAN

    help

      The ia64 architecture, as defined by:

        http://www.intel.com/design/itanium/arch_spec.htm