Revert "BFQ: Fixes and adds"

This reverts commit e1abaa001a5165ba91fedaa982abe89d5c58989a.
Revert "BFQ: Added scheduler"

This reverts commit ae41325ee69c7726afb3ffb240fc03b810340845.
Revert "block: prepare I/O context code for BFQ-v5r1"

This reverts commit a4b6906690b77490977f0cc2b4ba78796dac17ac.
Revert "block: prepare I/O context code for BFQ-v5r1 for 3.0"

This reverts commit 5275122fdbfb7070b5fc24beb41ad7534e06b047.