msm: cvp: Avoid NULL pointer dereference

Do not send HFI queue to DSP if the queue is not allocated and
initialized. It could happen after CVP and DSP SSR.

Change-Id: Ia344b63a119ca80d8de9e38ed5ac2585e27c06b3
Signed-off-by: George Shen <sqiao@codeaurora.org>