[CVE-2011-2496] mm: avoid wrapping vm_pgoff in mremap() and stack expansions

[Andy Whitcroft]

Fixes for this for every branch have already been applied.  However on
maverick/ti-omap4 a further commit is also needed compared to the master
branch, we are missing a commit that the master branch received via
stable.

Following this email is a patch for maverick/ti-omap4 which completes the
fix for this issue.  This is a cherry-pick from the commit as applied to
the master branch.

Proposing for maverick/ti-omap4.

-apw