mmc: core: check if CQE is already disabled before halt/unhalt

Upon any CQ error, the driver tries to halt the CQE first and
if it fails to halt, then CQE is disabled. The error handling
work function mmc_blk_cmdq_err() also tries to HALT the CQE
at couple of places and takes some action based on the HALT
success/error status. But since CQE is disabled, we should not
treat any errors of CQE halt/unhalt as critical and in fact,
we should not even attempt to halt/unhalt.

Change-Id: I6bef9f2c033f78ad0959954acc5d7627e8a92139
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>