LU-1115 kernel: software raid6 related BUG

LU-1115 kernel: software raid6 related BUG

Software raid6 hit BUGON in fs/bio.c:222 when raid chunk > 64k.
We pull upstream patch: 5b99c2ffa980528a197f26c7d876cceeccce8dd5
to deal with this issue.

port of b1_8 patch 747d905b631d90ce82521aac6a11d5d0eb0f45d8

Signed-off-by: yang sheng <ys@whamcloud.com>
Signed-off-by: Liu Ying <emoly.liu@intel.com>
Change-Id: I2b971f49dd621240460c9b9bf10f73f3f0bce32d
Reviewed-on: http://review.whamcloud.com/4526
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Johann Lombardi <johann.lombardi@intel.com>