ASoC: msm: Fix issues in proxy port driver due to early afe port enable.

After recent movement of afe_start to prepare the interrupts start
coming earlier from proxy port.
This results in proxy port driver not ready for interrupts. Start the
timer later to ensure processing of packet once trigger start happens.

Change-Id: Ie82d982b6c147afdef46a8c7bfe7234dd14486f1
Signed-off-by: Asish Bhattacharya <asishb@codeaurora.org>