drm/i915: Remove redundant device id from IS_IRONLAKE_M macro

IS_IRONLAKE_M can use the already defined intel_device_info.is_mobile for
this platform, so remove the instance of Ironlake's mobile device id from
the header file and replace it with an IS_MOBILE check.

v2:
 * Improved commit text. (Chris)

v3:
 * Rebased for EHL.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190326074057.27833-3-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -2304,6 +2304,8 @@ static inline unsigned int i915_sg_segment_size(void)
 
 #define IS_PLATFORM(dev_priv, p) (INTEL_INFO(dev_priv)->platform_mask & BIT(p))
 
+#define IS_MOBILE(dev_priv)	(INTEL_INFO(dev_priv)->is_mobile)
+
 #define IS_I830(dev_priv)	IS_PLATFORM(dev_priv, INTEL_I830)
 #define IS_I845G(dev_priv)	IS_PLATFORM(dev_priv, INTEL_I845G)
 #define IS_I85X(dev_priv)	IS_PLATFORM(dev_priv, INTEL_I85X)
@@ -2319,7 +2321,9 @@ static inline unsigned int i915_sg_segment_size(void)
 #define IS_G4X(dev_priv)	(IS_G45(dev_priv) || IS_GM45(dev_priv))
 #define IS_PINEVIEW(dev_priv)	IS_PLATFORM(dev_priv, INTEL_PINEVIEW)
 #define IS_G33(dev_priv)	IS_PLATFORM(dev_priv, INTEL_G33)
-#define IS_IRONLAKE_M(dev_priv)	(INTEL_DEVID(dev_priv) == 0x0046)
+#define IS_IRONLAKE(dev_priv)	IS_PLATFORM(dev_priv, INTEL_IRONLAKE)
+#define IS_IRONLAKE_M(dev_priv) \
+	(IS_PLATFORM(dev_priv, INTEL_IRONLAKE) && IS_MOBILE(dev_priv))
 #define IS_IVYBRIDGE(dev_priv)	IS_PLATFORM(dev_priv, INTEL_IVYBRIDGE)
 #define IS_IVB_GT1(dev_priv)	(IS_IVYBRIDGE(dev_priv) && \
 				 INTEL_INFO(dev_priv)->gt == 1)
@@ -2335,7 +2339,6 @@ static inline unsigned int i915_sg_segment_size(void)
 #define IS_CANNONLAKE(dev_priv)	IS_PLATFORM(dev_priv, INTEL_CANNONLAKE)
 #define IS_ICELAKE(dev_priv)	IS_PLATFORM(dev_priv, INTEL_ICELAKE)
 #define IS_ELKHARTLAKE(dev_priv)	IS_PLATFORM(dev_priv, INTEL_ELKHARTLAKE)
-#define IS_MOBILE(dev_priv)	(INTEL_INFO(dev_priv)->is_mobile)
 #define IS_HSW_EARLY_SDV(dev_priv) (IS_HASWELL(dev_priv) && \
 				    (INTEL_DEVID(dev_priv) & 0xFF00) == 0x0C00)
 #define IS_BDW_ULT(dev_priv)	(IS_BROADWELL(dev_priv) && \