After mq-deadline learned to deal with cgroups, the BLKCG_MAX_POLS value
became too small for all the elevators to be registered properly. The
following issue is seen:
```
calling bfq_init+0x0/0x8b @ 1
blkcg_policy_register: BLKCG_MAX_POLS too small
initcall bfq_init+0x0/0x8b returned -28 after 507 usecs
```
which renders BFQ non-functional.
Increase BLKCG_MAX_POLS to allow enough space for everyone.
Fixes: 08a9ad8bf6 ("block/mq-deadline: Add cgroup support")
Link: https://lore.kernel.org/lkml/8988303.mDXGIdCtx8@natalenko.name/
Signed-off-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210717123328.945810-1-oleksandr@natalenko.name
Signed-off-by: Jens Axboe <axboe@kernel.dk>
ec645dc966