microblaze: export assembly functions used by modules

Export __strncpy_user, memory_size, ioremap_bot for modules.

Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/mm/pgtable.c b/arch/microblaze/mm/pgtable.c
index 784557f..59bf233 100644
--- a/arch/microblaze/mm/pgtable.c
+++ b/arch/microblaze/mm/pgtable.c
@@ -42,6 +42,7 @@
 
 unsigned long ioremap_base;
 unsigned long ioremap_bot;
+EXPORT_SYMBOL(ioremap_bot);
 
 /* The maximum lowmem defaults to 768Mb, but this can be configured to
  * another value.