drm/i915: Rename i915_pipe_crc_ctl to i915_display_crc_ctl

In the same spirit than:

    drm/i915: Generalize the CRC command format for future work

    Let's move from writing 'A plane1' to 'pipe A plane1' to
    i915_pipe_crc_ctl. This will allow us to extend the interface to
    transcoders or DDIs in the future.

Let's rename the CRC control file to be more generic.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>