Revert "block: Switch from BFQ-v6r1 for 3.1.0 to BFQ-v6r2 for 3.1.0."

This reverts commit 78d0266781ff5c2e0e8593931f6c1ec905c79110.
Revert "block: Switch from BFQ-v6 for 3.1.0 to BFQ-v6r1 for 3.1.0."

This reverts commit a56a03e00a41b128b777615797f47d46414fe1cf.
Revert "block: Switch from BFQ-v5r1 for 3.1.0 to BFQ-v6 for 3.1.0."

This reverts commit f020f265d1c8c8102277fc6e9a16f21967133c61.
Revert "block: Switch from BFQ-v5 for 3.1.0 to BFQ-v5r1 for 3.1.0."

This reverts commit 37b88f05f60353e5cec5193f086f0f07d9e0ca48.
Revert "Merge remote-tracking branch 'github/cm-10.1' into cm-10.2-merge"

This reverts commit fa81c2194208661de88dc21263b117ec7070329f.
Patch1:block-prepare-I-O-context-code-for-BFQ-v7r2-for-3.1
Patch2:block-cgroups-kconfig-build-bits-for-BFQ-v7r2-3.1
Patch3:block-introduce-the-BFQ-v7r2-I-O-sched-for-3.1
Patch4:block-bfq-add-Early-Queue-Merge-EQM-to-BFQ-v7r2-for-3.1.0