ppc64: pie -- Add ppc64le relocation's processing

This cleans the assembly code, removing no more needed trick with the
register 2 (TOC pointer). As a consequence, the __export_restore_task_trampoline()
and __export_unmap_trampoline() are no more needed.

Thus, the changes introduced by the commit de9df910 ("Per architecture restorer
trampolines") in cr-restore.c are no more used but are not impacting
runtime code anyway.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>