sh: fix P4 iounmap() pass-through

Fix iounmap() of pass-through P4 addresses. Without this patch
iounmap() on the sh7780 rtc area results in a warning message.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/ioremap_32.c

@@ -119,7 +119,7 @@ void __iounmap(void __iomem *addr)
 	unsigned long seg = PXSEG(vaddr);
 	struct vm_struct *p;
 
-	if (seg < P3SEG || seg >= P3_ADDR_MAX || is_pci_memaddr(vaddr))
+	if (seg < P3SEG || vaddr >= P3_ADDR_MAX || is_pci_memaddr(vaddr))
 		return;
 
 #ifdef CONFIG_32BIT