[AVR32] Export clear_page symbol

Add missing EXPORT_SYMBOL(clear_page), allowing ext3 to be compiled
as a module.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/arch/avr32/kernel/avr32_ksyms.c b/arch/avr32/kernel/avr32_ksyms.c
index 7c4c761..80f55f8 100644
--- a/arch/avr32/kernel/avr32_ksyms.c
+++ b/arch/avr32/kernel/avr32_ksyms.c
@@ -29,6 +29,7 @@
  */
 EXPORT_SYMBOL(memset);
 EXPORT_SYMBOL(memcpy);
+EXPORT_SYMBOL(clear_page);
 
 /*
  * Userspace access stuff.