drm/i915: Remove HAS_PIPE_CONTROL()

The code using this was removed in:

  commit 88f23b8f
  Author: Chris Wilson <chris@chris-wilson.co.uk>
  Date:   Sun Dec 5 15:08:31 2010 +0000

      drm/i915: Avoid using PIPE_CONTROL on Ironlake
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1569,8 +1569,6 @@ struct drm_i915_file_private {
 
 #define HAS_IPS(dev)		(IS_ULT(dev))
 
-#define HAS_PIPE_CONTROL(dev) (INTEL_INFO(dev)->gen >= 5)
-
 #define HAS_DDI(dev)		(INTEL_INFO(dev)->has_ddi)
 #define HAS_POWER_WELL(dev)	(IS_HASWELL(dev))
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)