PCI hotplug: check ioremap() return value in ibmphp_ebda.c

check ioremap() return value.

Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/hotplug/ibmphp_ebda.c

@@ -261,6 +261,8 @@ int __init ibmphp_access_ebda (void)
 	debug ("returned ebda segment: %x\n", ebda_seg);
 	
 	io_mem = ioremap(ebda_seg<<4, 1);
+	if (!io_mem)
+		return -ENOMEM;
 	ebda_sz = readb(io_mem);
 	iounmap(io_mem);
 	debug("ebda size: %d(KiB)\n", ebda_sz);