parisc: export empty_zero_page

Needed by ext4 when built as a module.

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 78fe252..ce0da68 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -547,6 +547,7 @@
 }
 
 unsigned long *empty_zero_page __read_mostly;
+EXPORT_SYMBOL(empty_zero_page);
 
 void show_mem(void)
 {