spi: spi_bfin5xx.c: use resource_size()

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/spi_bfin5xx.c

@@ -1294,7 +1294,7 @@ static int __init bfin_spi_probe(struct platform_device *pdev)
 		goto out_error_get_res;
 	}
 
-	drv_data->regs_base = ioremap(res->start, (res->end - res->start + 1));
+	drv_data->regs_base = ioremap(res->start, resource_size(res));
 	if (drv_data->regs_base == NULL) {
 		dev_err(dev, "Cannot map IO\n");
 		status = -ENXIO;