drm/msm: fix zero device count HDCP repeater test cases

Fix the handling of HDCP repeaters to mark part II
of the authentication as failure if they do not have
any devices connected to them.

Change-Id: I6b21ed2ce9a280f7e200404b05d111508a6d3dd8
Signed-off-by: Abhinav Kumar <abhinavk@codeaurora.org>