variable dependencies in config.in files.

By moving drivers/input/config.in before drivers/char/Config.in
and drivers/usb/Config.in for arch/alpha and arch/mips(64),
several (7) instances of this message:
  forward declared symbol "CONFIG_INPUT" used in dependency list
and (6) instances of this one:
  forward declared symbol "CONFIG_SOUND_GAMEPORT" used in
  dependency list
can be removed.  (Yes, the latter one is for OSS drivers,
so it's not so important.)
   
It also adds one forward dependency for a USB joystick
in the input subsystem [still only for alpha and mips(64)].
Most other arches are already like this.