i2c-pca-isa: Add access check to legacy ioports

When probing i2c-pca-isa writes to legacy ioports, which crashes the kernel
if there is no device at that port.
This patch adds a check_legacy_ioport call, so probe fails gracefully
and thus prevents the oops.
Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-pca-isa.c

@@ -125,6 +125,13 @@ static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
 
 	dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
 
+#ifdef CONFIG_PPC_MERGE
+	if (check_legacy_ioport(base)) {
+		dev_err(dev, "I/O address %#08lx is not available\n", base);
+		goto out;
+	}
+#endif
+
 	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
 		dev_err(dev, "I/O address %#08lx is in use\n", base);
 		goto out;