mpt2sas: fix non-x86 crash on shutdown

Upstrem commit: 911ae943

There's a bug in the MSIX backup and restore routines that cause a crash on
non-x86 (direct access to PCI space not via read/write).  These routines are
unnecessary and were removed by the above commit, so also remove them from
stable to fix the crash.

Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>