Revert "bfq v7r6 patch3"

This reverts commit 4ef8bac81b4a480ad44de70fad95493111e62e02.
Revert "bfq v7r6 patch2"

This reverts commit 606029fb05ffe058c147797cc14303b5e2495dbd.
Revert "bfq v7r6 patch1"

This reverts commit 98b4d5fecf0c03e142175a05f9752f80a5757348.
cfq io scheduler as default