[PATCH] drm: fix implicit declaration build error on ia64

[Jani Nikula]

   drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_downstream_debug':
>> drivers/gpu/drm/drm_dp_helper.c:551:2: error: implicit declaration of
>> function 'seq_printf' [-Werror=implicit-function-declaration]
     seq_printf(m, "\tDP branch device present: %s\n",
     ^
>> drivers/gpu/drm/drm_dp_helper.c:559:3: error: implicit declaration of
>> function 'seq_puts' [-Werror=implicit-function-declaration]
     seq_puts(m, "\t\tType: DisplayPort\n");
     ^

Reported-by: kbuild test robot <fengguang.wu at intel.com>
References: https://lists.freedesktop.org/archives/intel-gfx/2016-September/106638.html
Fixes: 80209e5f2c42 ("drm: Add DP branch device info on debugfs")
Cc: Mika Kahola <mika.kahola at intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>

---

The commit being fixed is only in drm-intel tree. I failed at actually
testing this, but I presume this is the fix...
---
 drivers/gpu/drm/drm_dp_helper.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index a5365142cdba..894a6ac6f6e7 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -27,6 +27,7 @@
 #include <linux/errno.h>
 #include <linux/sched.h>
 #include <linux/i2c.h>
+#include <linux/seq_file.h>
 #include <drm/drm_dp_helper.h>
 #include <drm/drmP.h>
 
-- 
2.1.4