msm_fb: HDMI: Fix for HW reset issue on HDCP Reauth

On HDCP reauthentication, the HDCP link status register does not
get cleared unless the HDMI app clock is deasserted and asserted.
Stale values in the link status registers can potentially lead to
the HDCP HW block getting locked up resulting in a device reset.

Change-Id: I4952c64d4087e4303cbc75dbb61f66510b0a0798
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>