drm/i915: Make ibx_{enable,disable}_display_interrupt() static inlines

No reason why ibx_{enable,disable}_display_interrupt() couldn't be
static inlines instead of cpp macros.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448294777-13722-2-git-send-email-ville.syrjala@linux.intel.comReviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -2758,10 +2758,17 @@ ironlake_disable_display_irq(struct drm_i915_private *dev_priv, u32 mask);
 void ibx_display_interrupt_update(struct drm_i915_private *dev_priv,
 				  uint32_t interrupt_mask,
 				  uint32_t enabled_irq_mask);
-#define ibx_enable_display_interrupt(dev_priv, bits) \
-	ibx_display_interrupt_update((dev_priv), (bits), (bits))
-#define ibx_disable_display_interrupt(dev_priv, bits) \
-	ibx_display_interrupt_update((dev_priv), (bits), 0)
+static inline void
+ibx_enable_display_interrupt(struct drm_i915_private *dev_priv, uint32_t bits)
+{
+	ibx_display_interrupt_update(dev_priv, bits, bits);
+}
+static inline void
+ibx_disable_display_interrupt(struct drm_i915_private *dev_priv, uint32_t bits)
+{
+	ibx_display_interrupt_update(dev_priv, bits, 0);
+}
+
 
 /* i915_gem.c */
 int i915_gem_create_ioctl(struct drm_device *dev, void *data,