[IA64] export copy_page() to modules

[IA64] export copy_page() to modules

With the unionfs patch applied I get

ERROR: "copy_page" [fs/unionfs/unionfs.ko] undefined!

the other architectures (some, at least) export copy_page() so I guess ia64
should also do so.

To do this we need to move the copy_page() functions out of lib.a and into
built-in.o and add the EXPORT_SYMBOL().

Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>