drm: Always include the debugfs dentry in drm_crtc

Remove the counterproductive CONFIG_DEBUG_FS ifdef and just include
the debugfs dentry in drm_crtc always. This way we don't need
annoying ifdefs in the actual code with DEBUGFS=n. Also we don't
have these ifdefs around any of the other debugfs dentries either
so can't see why drm_crtc should be special.

This fixes the i915 DEBUGFS=n build because I assumed the dentry
would always be there.

Cc: Jani Nikula <jani.nikula@intel.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Fixes: e74c6aa9 ("drm/i915/fbc: Register per-crtc debugfs files")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211221193754.12287-1-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>

include/drm/drm_crtc.h

@@ -1135,14 +1135,12 @@ struct drm_crtc {
 	 */
 	spinlock_t commit_lock;
 
-#ifdef CONFIG_DEBUG_FS
 	/**
 	 * @debugfs_entry:
 	 *
 	 * Debugfs directory for this CRTC.
 	 */
 	struct dentry *debugfs_entry;
-#endif
 
 	/**
 	 * @crc: