[PATCH] drm: include linux/seq_file.h as needed

[Arnd Bergmann]

The addition of the debugfs info created references to seq_puts() and
seq_printf(), but relied on the debugfs header to be included implicitly,
which apparently doesn't happen all the time, as seen from this randconfig
build output:

drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_downstream_debug':
drivers/gpu/drm/drm_dp_helper.c:552:2: error: implicit declaration of function 'seq_printf' [-Werror=implicit-function-declaration]
drivers/gpu/drm/drm_dp_helper.c:560:3: error: implicit declaration of function 'seq_puts' [-Werror=implicit-function-declaration]

Adding the extra include brings back a clean build.

Fixes: 80209e5f2c42 ("drm: Add DP branch device info on debugfs")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 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 a07adf0a07db..3e6fe82c6d64 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>
 
-- 
2.9.0