[PATCH] AVR32: Don't try to iounmap P2 segment addresses

While ioremap() will happily map a physical address through the
P2 (uncached) segment when appropriate, iounmap() doesn't know how
to handle those mappings.

This patch makes iounmap() do the right thing, i.e. nothing, for
such mappings.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/avr32/mm/ioremap.c

@@ -77,6 +77,8 @@ void __iounmap(void __iomem *addr)
 
 	if ((unsigned long)addr >= P4SEG)
 		return;
+	if (PXSEG(addr) == P2SEG)
+		return;
 
 	p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
 	if (unlikely(!p)) {