DRM/i915: Remove i965_hpd_irq_setup.

After
"Convert HPD interrupts to make use of HPD pin assignment in encoders."
This function is now basically the same as i915_hpd_irq_setup().

Consolidating both functions in one requires one more check for
I915_HAS_HOTPLUG(dev) in the i965 code path and one more check for
IS_G4X(dev) in the i915 code path. These are considered harmless.

Signed-off-by: Egbert Eich <eich@suse.de>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Fixup patch conflict and make it compile.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>