sh: heartbeat: Shut up resource size warning.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/drivers/heartbeat.c b/arch/sh/drivers/heartbeat.c
index 23dd608..10c1828 100644
--- a/arch/sh/drivers/heartbeat.c
+++ b/arch/sh/drivers/heartbeat.c
@@ -78,7 +78,7 @@
 			hd->bit_pos[i] = i;
 	}
 
-	hd->base = (void __iomem *)res->start;
+	hd->base = (void __iomem *)(unsigned long)res->start;
 
 	setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd);
 	platform_set_drvdata(pdev, hd);