disp: msm: dp: delay hotplug connect notification

Delay the hotplug connect notification to check for any test
requests issued by the sink. This will avoid unwanted connection
event callbacks.

CRs-Fixed: 2565704
Change-Id: Id7a04dbbb5ad5b86c3791ac2db5de2c92e98fc46
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>