drm/sti: include linux/seq_file.h where needed

The sti drm driver has a lot of debugfs interface that cause
build errors in some configurations when seq_file.h is not
included implicitly:

drm/sti/sti_mixer.c: In function 'mixer_dbg_ctl':
drm/sti/sti_mixer.c:88:2: error: implicit declaration of function 'seq_puts' [-Werror=implicit-function-declaration]
drm/sti/sti_mixer.c:91:4: error: implicit declaration of function 'seq_printf' [-Werror=implicit-function-declaration]
drm/sti/sti_gdp.c: In function 'gdp_dbg_ctl':
drm/sti/sti_gdp.c:146:2: error: implicit declaration of function 'seq_puts' [-Werror=implicit-function-declaration]
drm/sti/sti_gdp.c:149:4: error: implicit declaration of function 'seq_printf' [-Werror=implicit-function-declaration]
drm/sti/sti_gdp.c: In function 'gdp_dbg_show':
drm/sti/sti_gdp.c:208:32: error: dereferencing pointer to incomplete type 'struct seq_file'

This adds an explicit #include statement in all of the affected files.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1462830733-1710590-2-git-send-email-arnd@arndb.de

drivers/gpu/drm/sti/sti_cursor.c

@@ -6,6 +6,8 @@
  * License terms:  GNU General Public License (GPL), version 2
  */
 
+#include <linux/seq_file.h>
+
 #include <drm/drm_atomic.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>

drivers/gpu/drm/sti/sti_gdp.c

@@ -5,6 +5,7 @@
  *          for STMicroelectronics.
  * License terms:  GNU General Public License (GPL), version 2
  */
+#include <linux/seq_file.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_fb_cma_helper.h>

drivers/gpu/drm/sti/sti_hda.c

@@ -8,6 +8,7 @@
 #include <linux/component.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/seq_file.h>
 
 #include <drm/drmP.h>
 #include <drm/drm_atomic_helper.h>

drivers/gpu/drm/sti/sti_hqvdp.c

@@ -7,6 +7,7 @@
 #include <linux/component.h>
 #include <linux/firmware.h>
 #include <linux/reset.h>
+#include <linux/seq_file.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_fb_cma_helper.h>

drivers/gpu/drm/sti/sti_mixer.c

@@ -5,6 +5,7 @@
  *          for STMicroelectronics.
  * License terms:  GNU General Public License (GPL), version 2
  */
+#include <linux/seq_file.h>
 
 #include "sti_compositor.h"
 #include "sti_mixer.h"

drivers/gpu/drm/sti/sti_tvout.c

@@ -12,6 +12,7 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
+#include <linux/seq_file.h>
 
 #include <drm/drmP.h>
 #include <drm/drm_crtc_helper.h>

drivers/gpu/drm/sti/sti_vid.c

@@ -3,6 +3,7 @@
  * Author: Fabien Dessenne <fabien.dessenne@st.com> for STMicroelectronics.
  * License terms:  GNU General Public License (GPL), version 2
  */
+#include <linux/seq_file.h>
 
 #include <drm/drmP.h>