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/at91sam9263.h b/arch/arm/include/asm/arch-at91/at91sam9263.h
index bfd408b..2a1d6ee 100644
--- a/arch/arm/include/asm/arch-at91/at91sam9263.h
+++ b/arch/arm/include/asm/arch-at91/at91sam9263.h
@@ -128,6 +128,7 @@
  * Other misc defines
  */
 #define ATMEL_PIO_PORTS		5		/* this SoCs has 5 PIO */
+#define ATMEL_BASE_PIO		ATMEL_BASE_PIOA
 
 /*
  * Cpu Name