drm/sti: rename files and functions

replace all "sti_drm_" occurences by "sti_"

Signed-off-by: Vincent Abriou <vincent.abriou@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
diff --git a/drivers/gpu/drm/sti/sti_cursor.c b/drivers/gpu/drm/sti/sti_cursor.c
index cd12403..2868909a 100644
--- a/drivers/gpu/drm/sti/sti_cursor.c
+++ b/drivers/gpu/drm/sti/sti_cursor.c
@@ -8,7 +8,7 @@
 #include <drm/drmP.h>
 
 #include "sti_cursor.h"
-#include "sti_drm_plane.h"
+#include "sti_plane.h"
 #include "sti_vtg.h"
 
 /* Registers */