mhi: controller: decrease auto-suspend timeout

Reduce auto-suspend timeout from 1000ms to 250ms
to make it aggressive for power saving.

CRs-Fixed: 2308871
Change-Id: I9733d1b8f0317e3f5d252f979fef68bdedfd196e
Acked-by: Bhaumik Vasav Bhatt <bbhatt@qti.qualcomm.com>
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>