sparc: Export symbols for ZERO_PAGE usage in modules.

ext4 uses ZERO_PAGE(0) to zero out blocks.  We need to export
different symbols in different arches for the usage of ZERO_PAGE
in modules.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index 8c2b50e..4cad0b3 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -160,6 +160,7 @@
 extern unsigned int sparc_ramdisk_size;
 
 struct page *mem_map_zero __read_mostly;
+EXPORT_SYMBOL(mem_map_zero);
 
 unsigned int sparc64_highest_unlocked_tlb_ent __read_mostly;