ARM: S3C64XX: Add USB external clock definition

This adds the xusbxti clock to S3C64XX platform.

Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/arch/arm/plat-samsung/include/plat/clock.h b/arch/arm/plat-samsung/include/plat/clock.h
index 60b6269..efbc984 100644
--- a/arch/arm/plat-samsung/include/plat/clock.h
+++ b/arch/arm/plat-samsung/include/plat/clock.h
@@ -74,6 +74,7 @@
 extern struct clk clk_h2;
 extern struct clk clk_27m;
 extern struct clk clk_48m;
+extern struct clk clk_xusbxti;
 
 extern int clk_default_setrate(struct clk *clk, unsigned long rate);
 extern struct clk_ops clk_ops_def_setrate;