avr32: fix build error in atstk1006_defconfig

[Josh Wu]

fixed the following compile error when use avr32 atstk1006_defconfig:
  drivers/mtd/nand/atmel_nand.c: In function 'pmecc_err_location':
  drivers/mtd/nand/atmel_nand.c:639: error: implicit declaration of function 'writel_relaxed'

which was introduced by commit 1c7b874d33b463 ("mtd: at91: atmel_nand: add Programmable Multibit ECC controller support").
The PMECC for nand flash code uses writel_relaxed(). But in avr32, there is no macro "writel_relaxed" defined. This patch add writex_relaxed macro definitions.

Signed-off-by: Josh Wu <josh.wu at atmel.com>
Acked-by: Havard Skinnemoen <havard at skinnemoen.net>
Acked-by: Hans-Christian Egtvedt <egtvedt at samfundet.no>

---
arch/avr32/include/asm/io.h |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/avr32/include/asm/io.h b/arch/avr32/include/asm/io.h
index cf60d0a..fc6483f 100644
--- a/arch/avr32/include/asm/io.h
+++ b/arch/avr32/include/asm/io.h
@@ -165,6 +165,10 @@ BUILDIO_IOPORT(l, u32)
 #define readw_be			__raw_readw
 #define readl_be			__raw_readl
 
+#define writeb_relaxed			writeb
+#define writew_relaxed			writew
+#define writel_relaxed			writel
+
 #define writeb_be			__raw_writeb
 #define writew_be			__raw_writew
 #define writel_be			__raw_writel