drm/i915: ilk-ivb: replace !is_pch_edp() with port==PORT_A

On ILK-IVB the CPU side eDP is always on port-A.

Also reduce somewhat the debug verbosity.

v2:
- reduce debug verbosity

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>