Add very basic implementation of collie PDA emulation. The system lacks
LoCoMo and graphics/sound emulation. Linux kernel boots up to mounting
rootfs (theoretically it can be provided in pflash images).

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>