mmc: cmdq_hci: Fix key index refcnt issue with metadata encryption

When metadata encryption is enabled, below errors are observed
from pfk driver.

[   44.754642] internal error, ref count should never be negative index 2

For discard commands, cq_host->ops->crypto_cfg_end() is being invoked
without its corresponding cq_host->ops->crypto_cfg() call. This is fine
until now, because ICE driver's  msm_host->ice.vops->config_end() would
do nothing if req->bio is NULL. But with metadata encryption this may
not be NULL, thus resulting into refcnt mismatch for that key.

Change-Id: I1609eb8506d0d19944c536adbd9253da2a45c47c
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>