drm: i915: fix build when DEBUG_FS is disabled

This clearly had never gotten tested, probably because you need a fairly
minimal configuration in order to disable DEBUG_FS (several other
options select it).

The dummy inline functions that were used for the no-DEBUG_FS case were
missing the argument names in the declarations.

Fixes: 1dac891c ("drm/i915: Register debugfs interface last")
Reported-and-tested-by: Jörg Otte <jrg.otte@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpu/drm/i915/i915_drv.h

@@ -3651,8 +3651,8 @@ void i915_debugfs_unregister(struct drm_i915_private *dev_priv);
 int i915_debugfs_connector_add(struct drm_connector *connector);
 void intel_display_crc_init(struct drm_device *dev);
 #else
-static inline int i915_debugfs_register(struct drm_i915_private *) {return 0;}
-static inline void i915_debugfs_unregister(struct drm_i915_private *) {}
+static inline int i915_debugfs_register(struct drm_i915_private *dev_priv) {return 0;}
+static inline void i915_debugfs_unregister(struct drm_i915_private *dev_priv) {}
 static inline int i915_debugfs_connector_add(struct drm_connector *connector)
 { return 0; }
 static inline void intel_display_crc_init(struct drm_device *dev) {}