spi: spi_mpc8xxx.c: use resource_size()

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

drivers/spi/spi_mpc8xxx.c

@@ -566,7 +566,7 @@ mpc8xxx_spi_probe(struct device *dev, struct resource *mem, unsigned int irq)
 
 	init_completion(&mpc8xxx_spi->done);
 
-	mpc8xxx_spi->base = ioremap(mem->start, mem->end - mem->start + 1);
+	mpc8xxx_spi->base = ioremap(mem->start, resource_size(mem));
 	if (mpc8xxx_spi->base == NULL) {
 		ret = -ENOMEM;
 		goto put_master;