[ARM] 4825/1: adds support for YL9200 board

1. Configuration file for YL9200
2. Board file fro YL9200

Adds support for the UCdragon YL9200 board available widly in China
Signed-off-by: Nsteve birtles <arm_kernel_development@micromark.net.cn>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>