mmc: cmdq_hci: release runtime PM reference after halt/unhalt

Currently we are not releasing the runtime PM reference count after
halt/unhalt completion which basically keeps the runtime PM state to
active forever. Fix this by releasing the PM reference count on
completion of halt/unhalt operation.

Change-Id: I28a37917b49acde7f5d75bf9a639d0eb67a1c169
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>