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 <arnd@arndb.de>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

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

@@ -13,6 +13,7 @@
 #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

@@ -16,6 +16,7 @@
 #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

@@ -14,6 +14,7 @@
 #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"