drm/msm/hdcp: Account for in progress stream management

If stream registration is invoked while HDCP is still authenticating,
the new stream information may not get sent to the downstream repeater.

Check if stream management is already in progress during stream
registration, and queue another round of stream management if so.

Change-Id: I497e9a4da310870fe792293033f1fb0ce8fbee4c
Signed-off-by: Christopher Braga <cbraga@codeaurora.org>