[ARM] 4300/1: Add picotux 200 ARM board

Add the picotux 200 ARM board:
 - Enable its machine type in the filter in head.S
 - Add configuration option
 - Add board initialisation
 - Add default configuration

Signed-off-by: Simon Richter <Simon.Richter@kleinhenz.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>