integrate backport of 5 line mpt2sas fix

[Noa Resare <noa@spotify.com>]

Hello friends,

I'd like to ask you to cherry pick a 5 line change from the mainline linux kernel with ID ebda4d38df542e1ff4747c4daadfc7da250b4fa6 that resolves an issue we have been seeing with segfaulting vendor provided binary tools. This change has been thoroughly tested in our production environment with a kernel very close to 2.6.32-45 in Debian squeeze

For additional details about our issues and the process leading up to identifying the change, have a look at: http://labs.spotify.com/2013/01/28/finding-the-right-needle-in-the-kernel-haystack/

With kind regards

Noa Resare, Spotify Infrastructure Engineering.