HID: intel-ish-hid: Fix potential race condition

Although unlikely but it is possible that when a connect or disconnect
request is issued to the firmware, before the response comes, user
terminates the client session. In this case when the response is arrived
there is no matching client instance in the list of currently active
clients. In this case, don't issue call to wake up a waiting client.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>