CVE-2010-2070 kernel-xen: ia64-xen: unset be from the task psr

[Eugene Teo <eugeneteo () kernel sg>]

https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2010-2070
http://xenbits.xensource.com/xen-4.0-testing.hg?rev/42caadb14edb

An unprivileged user can turn on BE by modifying the user mask of the 
PSR, resulting in at least a local denial of service. This issue can be 
triggered the same way CVE-2006-0742 was triggered, but both are not 
related (not a regression).

Thanks, Eugene
--
main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i); }