[ARM] export copy_page

Martin Michlmayr reported that fuse complains:
  ERROR: "copy_page" [fs/fuse/fuse.ko] undefined!

so export the needed function.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/armksyms.c

@@ -179,3 +179,5 @@ EXPORT_SYMBOL(_find_next_zero_bit_be);
 EXPORT_SYMBOL(_find_first_bit_be);
 EXPORT_SYMBOL(_find_next_bit_be);
 #endif
+
+EXPORT_SYMBOL(copy_page);