[AVR32] Fix build error in parse_tag_rdimg()

This code is inside an #ifdef with a misspelled config symbol, so it
hasn't been used for a long time. Fix it before fixing the config
symbol to keep bisection working.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>

arch/avr32/kernel/setup.c

@@ -323,7 +323,7 @@ static int __init parse_tag_rdimg(struct tag *tag)
 		return 0;
 	}
 
-	ret = add_reserved_region(mem->start, mem->start + mem->size - 1,
+	ret = add_reserved_region(mem->addr, mem->addr + mem->size - 1,
 				  "initrd");
 	if (ret) {
 		printk(KERN_WARNING