drm: msm: Fix build when legacy fbdev support isn't set

The DRM_KMS_FB_HELPER config is selected only when DRM_MSM_FBDEV config is
selected. The driver accesses drm_fb_helper_* functions even when legacy fbdev
support is disabled in msm. Wrap around these functions with #ifdef checks to
prevent build break.
Signed-off-by: Archit Taneja <architt@codeaurora.org>

drivers/gpu/drm/msm/msm_drv.c

@@ -21,9 +21,11 @@
 
 static void msm_fb_output_poll_changed(struct drm_device *dev)
 {
+#ifdef CONFIG_DRM_MSM_FBDEV
 	struct msm_drm_private *priv = dev->dev_private;
 	if (priv->fbdev)
 		drm_fb_helper_hotplug_event(priv->fbdev);
+#endif
 }
 
 static const struct drm_mode_config_funcs mode_config_funcs = {
@@ -419,9 +421,11 @@ static void msm_preclose(struct drm_device *dev, struct drm_file *file)
 
 static void msm_lastclose(struct drm_device *dev)
 {
+#ifdef CONFIG_DRM_MSM_FBDEV
 	struct msm_drm_private *priv = dev->dev_private;
 	if (priv->fbdev)
 		drm_fb_helper_restore_fbdev_mode_unlocked(priv->fbdev);
+#endif
 }
 
 static irqreturn_t msm_irq(int irq, void *arg)