drivers/ide/tx4938ide.c: use resource_size()

Use resource_size() for devm_request_mem_region.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/ide/tx4938ide.c b/drivers/ide/tx4938ide.c
index ea89fdd..fd59c0d 100644
--- a/drivers/ide/tx4938ide.c
+++ b/drivers/ide/tx4938ide.c
@@ -146,7 +146,7 @@
 		return -ENODEV;
 
 	if (!devm_request_mem_region(&pdev->dev, res->start,
-				     res->end - res->start + 1, "tx4938ide"))
+				     resource_size(res), "tx4938ide"))
 		return -EBUSY;
 	mapbase = (unsigned long)devm_ioremap(&pdev->dev, res->start,
 					      8 << pdata->ioport_shift);