mmc: cmdq_hci: Helper API/info in cmdq for halt

This patch adds following helper API/info -

1. cmdq_halt_poll to halt the controller using polling
method. This is to be mainly used in case of an error
from cmdq_irq context.

2. Adds num_cq_slots & dcmd_cq_slot info to
mmc_host structure. This can be useful info
for mmc host structure like in case of handling
of multiple error requests

3. Adds CMDQ_STATE_CQ_DISABLE for cmdq host.
In case of an error if halt also fails, CQE error handling
code will disable CQ. So block layer needs to know
- to not pull any requests in such case.

Change-Id: I8e9a8d5094db82336917fcca4361ce84316c34ef
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>