[ARM] 3575/1: netX: board support for NXDB500 development board

Patch from Sascha Hauer

This patch adds the board specific code for the Hilscher NXDB500
development board.

Signed-off-by: Robert Schwebel <r.schwebel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>