drm/i915: kill superflous IS_I855 macro

It is identical to I85X. Use that one instead.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
[anholt: fix conflicts against the display function pointer stuff]
Signed-off-by: NEric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_drv.h

@@ -946,7 +946,6 @@ extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
 #define IS_I830(dev) ((dev)->pci_device == 0x3577)
 #define IS_845G(dev) ((dev)->pci_device == 0x2562)
 #define IS_I85X(dev) ((dev)->pci_device == 0x3582)
-#define IS_I855(dev) ((dev)->pci_device == 0x3582)
 #define IS_I865G(dev) ((dev)->pci_device == 0x2572)
 
 #define IS_I915G(dev) ((dev)->pci_device == 0x2582 || (dev)->pci_device == 0x258a)

drivers/gpu/drm/i915/intel_display.c

@@ -4291,7 +4291,7 @@ void intel_init_clock_gating(struct drm_device *dev)
 		dstate |= DSTATE_PLL_D3_OFF | DSTATE_GFX_CLOCK_GATING |
 			DSTATE_DOT_CLOCK_GATING;
 		I915_WRITE(D_STATE, dstate);
-	} else if (IS_I855(dev) || IS_I865G(dev)) {
+	} else if (IS_I85X(dev) || IS_I865G(dev)) {
 		I915_WRITE(RENCLK_GATE_D1, SV_CLOCK_GATE_DISABLE);
 	} else if (IS_I830(dev)) {
 		I915_WRITE(DSPCLK_GATE_D, OVRUNIT_CLOCK_GATE_DISABLE);
@@ -4375,7 +4375,7 @@ static void intel_init_display(struct drm_device *dev)
 	else if (IS_I865G(dev))
 		dev_priv->display.get_display_clock_speed =
 			i865_get_display_clock_speed;
-	else if (IS_I855(dev))
+	else if (IS_I85X(dev))
 		dev_priv->display.get_display_clock_speed =
 			i855_get_display_clock_speed;
 	else /* 852, 830 */