radio-iris: Perform FM cleanup in uninterruptible task state

When FM application is force killed, wait for controller to successfully
complete disable sequence, else following FM turn on will fail.
On forced killing, device node is released but not from userspace. Hence
do not send controller response to userspace in this state.

CRs-Fixed: 967734
Change-Id: I96c1f577fce2bd5fcdd0e5b2b6bc2000d61a0bce
Signed-off-by: Mingbo Zhang <mingboz@codeaurora.org>
Signed-off-by: Rupesh Tatiya <rtatiya@codeaurora.org>