drm/i915: Delete duplicate #defines added for DCx

Delete the duplicate #defines introduced by:

	commit 6b457d31
	Author: A.Sunil Kamath <sunil.kamath@intel.com>
	Date:   Thu Apr 16 14:22:09 2015 +0530

		drm/i915/skl: Implement enable/disable for Display C5 state.
Signed-off-by: Chandra Konduru <chandra.konduru@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -7282,12 +7282,6 @@ enum skl_disp_power_wells {
 #define DC_STATE_EN			0x45504
 #define  DC_STATE_EN_UPTO_DC5		(1<<0)
 #define  DC_STATE_EN_DC9		(1<<3)
-
-/*
-* SKL DC
-*/
-#define  DC_STATE_EN			0x45504
-#define  DC_STATE_EN_UPTO_DC5		(1<<0)
 #define  DC_STATE_EN_UPTO_DC6		(2<<0)
 #define  DC_STATE_EN_UPTO_DC5_DC6_MASK   0x3