GitLab

Add functionality to test-iosched so that it could simulate the
ROW scheduler behaviour. The main additions are:
- 3 distinct requests queue with counters
- support for urgent request pending
- reinsert request implementation (callback + dispatch behavior)

Change-Id: I83b5d9e3d2b8cd9a2353afa6a3e6a4cbc83b0cd4
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>
Signed-off-by: Lee Susman <lsusman@codeaurora.org>