drm/i915: don't limit Haswell CRT encoder to pipe A

drm/i915: don't limit Haswell CRT encoder to pipe A

This is a full revert of 2a5742303a47f5502ef7c0be3e1cca1a2b0c2c51:
    drm/i915: account for only one PCH receiver on Haswell

Now that the PCH code is fixed to be able use the only PCH transcoder
independently of the pipe and CPU transcoder, we can revert this.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Resolve conflict due to the rebasing of dinq on top of
drm-next.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>