arm926ejs/at91/lowlevel_init.S: fix defines

atmel rework changed define names which broke this file

Signed-off-by: Eric BĂ©nard <eric@eukrea.com>
diff --git a/arch/arm/include/asm/arch-at91/at91sam9261.h b/arch/arm/include/asm/arch-at91/at91sam9261.h
index f8048d5..c85fd29 100644
--- a/arch/arm/include/asm/arch-at91/at91sam9261.h
+++ b/arch/arm/include/asm/arch-at91/at91sam9261.h
@@ -125,6 +125,7 @@
  * Other misc defines
  */
 #define ATMEL_PIO_PORTS		3		/* theese SoCs have 3 PIO */
+#define ATMEL_BASE_PIO		ATMEL_BASE_PIOA
 
 /*
  * SoC specific defines