drm/omapdrm: include pinctrl/consumer.h where needed

In some configurations, we can build the OMAP dss driver without
implictly including the pinctrl consumer definitions, causing
a build error:

gpu/drm/omapdrm/dss/dss.c: In function 'dss_runtime_suspend':
gpu/drm/omapdrm/dss/dss.c:1268:2: error: implicit declaration of function 'pinctrl_pm_select_sleep_state' [-Werror=implicit-function-declaration]

This adds an explicit #include.

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

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

···
 #include <linux/delay.h>
 #include <linux/seq_file.h>
 #include <linux/clk.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/gfp.h>