disp: msm: fix driver unload issues in gki config

Resolves segmentation fault during driver unload in GKI
configuration, caused by repeated debugfs destroy calls.
Also removes redundant unload calls.

Change-Id: I20a8efc1916b9a60766f9c7714a4b458aa518566
Signed-off-by: Orion Brody <obrody@codeaurora.org>

msm/msm_kms.h

@@ -116,6 +116,8 @@ struct msm_kms_funcs {
 	/* debugfs: */
 	int (*debugfs_init)(struct msm_kms *kms, struct drm_minor *minor);
 #endif
+	/* destroys debugfs */
+	void (*debugfs_destroy)(struct msm_kms *kms);
 	/* handle continuous splash  */
 	int (*cont_splash_config)(struct msm_kms *kms);
 	/* check for continuous splash status */