drm/i915: Pass cpu transcoder to assert_pipe()

drm/i915: Pass cpu transcoder to assert_pipe()

In order to eliminate intel_pipe_to_cpu_transcoder() (and its
crtc->config usage) let's pass the cpu transcoder to
assert_pipe() so we don't have to do the pipe->cpu transcoder
lookup on HSW+.

On VLV/CHV this can get called during eDP init, which
happens before crtc->config->cpu_transcoder is even
populated. So currently we're always reading PIPECONF(A)
there even if we're trying to check the state of some
other pipe.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191112163812.22075-4-ville.syrjala@linux.intel.com
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>