msm: mdss: dp: fix HDCP 1.x state transitions

Fix HDCP 1.x state transitions by ensuring that transitions to
authenticating state can be made from both an uninitialized and
a failure state, and making sure that authentication thread is
synchronously canceled before transitioning to a disabled
state.

CRs-Fixed: 2006096
Change-Id: Ic097e16451166f589acbd7c23f87bd9b4c1a65f3
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>