drm/i915/bdw: Add BDW PCH check first

Early platforms use the same PCH as HSW, and to avoid triggering the
!ULT, and !HSW warnings, simply put it first in the search.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>