drm/i915/hdcp: pass the context to the HDCP GSC message interface

drm/i915/hdcp: pass the context to the HDCP GSC message interface

The opaque HDCP GSC context nicely abstracts the differences between
drivers. Pass that instead of struct drm_i915_private or struct
xe_device to intel_hdcp_gsc_msg_send(). We can store the driver specific
data in the context.

This lets us drop the dependency on i915_drv.h from
intel_hdcp_gsc_message.c.

Cc: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://lore.kernel.org/r/df1653212f9014e717701b017e78e0017884b870.1745524803.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>