drm: bridge: dw-hdmi: add hdcp1.4 support

drm: bridge: dw-hdmi: add hdcp1.4 support

First, write hdcp key by "ProvisioningTool" if you want to
enable hdcp function, or else will auth fail.

To check whether the hdcp is enable or not
  #cat /sys/class/misc/hdmi_hdcp1x/enable
  0:hdcp is disabled
  1:hdcp is enabled, hdmi screen will be pink if it is failed;
  2:hdcp is enabled, hdmi screen will be normal if it is failed;

Enable or disable hdcp function
  #echo 0 > /sys/class/misc/hdmi_hdcp1x/enable
  #echo 1 > /sys/class/misc/hdmi_hdcp1x/enable
  #echo 2 > /sys/class/misc/hdmi_hdcp1x/enable

Get the status of hdcp
  #cat /sys/class/misc/hdmi_hdcp1x/status
  The result will be one of the follow list:
    hdcp disable;
    hdcp_auth_start
    hdcp_auth_success;
    hdcp_auth_fail;
    unknown status.

Change-Id: Iac6c7d6a1196ce9cf2869d7916bbe6c8941ec13b
Signed-off-by: xuhuicong <xhc@rock-chips.com>