strider: Add DP501 support for cpu model

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/gdsys/common/dp501.h b/board/gdsys/common/dp501.h
index 8dc3215..b98b54e 100644
--- a/board/gdsys/common/dp501.h
+++ b/board/gdsys/common/dp501.h
@@ -26,5 +26,6 @@
 
 void dp501_powerup(u8 addr);
 void dp501_powerdown(u8 addr);
+int dp501_probe(unsigned screen, bool power);
 
 #endif