msm: mdss: Trigger idle fallback when no update due to touch

Trigger an idle fallback with a reasonable timeout value when
there is no update despite of a touch event and idle_time is 0.
This will reset the refresh rate to minimum fps.

CRs-Fixed: 2003247
Change-Id: I4a2964038f23984bf1ea39c63bf679d80ad12cba
Signed-off-by: Krishna Manikandan <mkrishn@codeaurora.org>