misc/mei/hdcp: Enabling the HDCP authentication

Request to ME to configure a port as authenticated.

On Success, ME FW will mark the port as authenticated and provides
HDCP cipher with the encryption keys.

Enabling the Authentication can be requested once all stages of
HDCP2.2 authentication is completed by interacting with ME FW.

Only after this stage, driver can enable the HDCP encryption for
the port, through HW registers.

v2: Rebased.
v3:
  cldev is passed as first parameter [Tomas]
  Redundant comments and cast are removed [Tomas]
v4:
  %zd for ssize_t [Alexander]
  %s/return -1/return -EIO [Alexander]
  Style and typos fixed [Uma]
v5: Rebased.
v6:
  Collected the Rb-ed by.
  Rebased.
v7:
  Adjust to the new mei interface.
  Fix for Kdoc.
v8:
  K-Doc addition. [Tomas]
v9:
  renamed func as mei_hdcp_* [Tomas]
  Inline function is defined for DDI index [Tomas]
v10:
  K-Doc fix. [Tomas]
v11:
  Rebased.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1550772730-23280-14-git-send-email-ramalingam.c@intel.com