ia64/sparc: fix local DoS with corrupted ELFs (CVE-2006-4538)

This patch prevents cross-region mappings
on IA64 and SPARC which could lead to system crash.

Adrian Bunk:
Adapted to 2.6.16.

Signed-Off-By: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>