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

The omapdrm driver relies on this header to be included
implicitly, but this does not always work, and I get
this error in randconfig builds:

gpu/drm/omapdrm/dss/hdmi_phy.c: In function 'hdmi_phy_dump':
gpu/drm/omapdrm/dss/hdmi_phy.c:34:2: error: implicit declaration of function 'seq_printf' [-Werror=implicit-function-declaration]
gpu/drm/omapdrm/dss/hdmi_wp.c: In function 'hdmi_wp_dump':
gpu/drm/omapdrm/dss/hdmi_wp.c:26:2: error: implicit declaration of function 'seq_printf' [-Werror=implicit-function-declaration]
gpu/drm/omapdrm/dss/hdmi_pll.c: In function 'hdmi_pll_dump':
gpu/drm/omapdrm/dss/hdmi_pll.c:30:2: error: implicit declaration of function 'seq_printf' [-Werror=implicit-function-declaration]

This adds the #include statements in all files that have
a seq_printf statement.

Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/gpu/drm/omapdrm/dss/hdmi_phy.c

···
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <video/omapdss.h>
 
 #include "dss.h"

drivers/gpu/drm/omapdrm/dss/hdmi_pll.c

···
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
+#include <linux/seq_file.h>
 
 #include <video/omapdss.h>
 

drivers/gpu/drm/omapdrm/dss/hdmi_wp.c

···
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/seq_file.h>
 #include <video/omapdss.h>
 
 #include "dss.h"

drivers/gpu/drm/omapdrm/omap_debugfs.c

···
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/seq_file.h>
+
 #include <drm/drm_crtc.h>
 #include <drm/drm_fb_helper.h>
 

drivers/gpu/drm/omapdrm/omap_dmm_tiler.c

···
 #include <linux/module.h>
 #include <linux/platform_device.h> /* platform_device() */
 #include <linux/sched.h>
+#include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/time.h>
 #include <linux/vmalloc.h>

drivers/gpu/drm/omapdrm/omap_fb.c

···
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/seq_file.h>
+
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 

drivers/gpu/drm/omapdrm/omap_gem.c

···
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/seq_file.h>
 #include <linux/shmem_fs.h>
 #include <linux/spinlock.h>
 #include <linux/pfn_t.h>