drm/msm: dsi: fix compile errors when CONFIG_GPIOLIB=n

I'm not sure where, exactly, but somewhere in here we must be relying on an implicit include.

drivers/gpu/drm/msm/dsi/dsi_host.c: In function ‘dsi_host_init_panel_gpios’:
drivers/gpu/drm/msm/dsi/dsi_host.c:1356:2: error: implicit declaration of function ‘devm_gpiod_get’ [-Werror=implicit-function-declaration]
msm_host->disp_en_gpio = devm_gpiod_get(panel_device,
^
drivers/gpu/drm/msm/dsi/dsi_host.c:1356:25: warning: assignment makes pointer from integer without a cast [enabled by default]
msm_host->disp_en_gpio = devm_gpiod_get(panel_device,

                         ^

drivers/gpu/drm/msm/dsi/dsi_host.c:1364:3: error: implicit declaration of function ‘gpiod_direction_output’ [-Werror=implicit-function-declaration]
ret = gpiod_direction_output(msm_host->disp_en_gpio, 0);
^
drivers/gpu/drm/msm/dsi/dsi_host.c:1371:20: warning: assignment makes pointer from integer without a cast [enabled by default]

  msm_host->te_gpio = devm_gpiod_get(panel_device, "disp-te");
                    ^

drivers/gpu/drm/msm/dsi/dsi_host.c:1378:3: error: implicit declaration of function ‘gpiod_direction_input’ [-Werror=implicit-function-declaration]
ret = gpiod_direction_input(msm_host->te_gpio);
^
drivers/gpu/drm/msm/dsi/dsi_host.c: In function ‘msm_dsi_host_power_on’:
drivers/gpu/drm/msm/dsi/dsi_host.c:1918:3: error: implicit declaration of function ‘gpiod_set_value’ [-Werror=implicit-function-declaration]
gpiod_set_value(msm_host->disp_en_gpio, 1);
^

---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 1 +
 1 file changed, 1 insertion(+)

index 956b22492c9a..98aae759f2fd 100644
@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/interrupt.h>
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>

1.9.1