drm/msm: add moduleparam to disable fbdev

Useful to avoid recompiling to disable fbdev.  Useful because otherwise
the first modeset happens under console_lock (ie. debugging sadness).
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_drv.c

@@ -54,6 +54,12 @@ module_param(reglog, bool, 0600);
 #define reglog 0
 #endif
 
+#ifdef CONFIG_DRM_MSM_FBDEV
+static bool fbdev = true;
+MODULE_PARM_DESC(fbdev, "Enable fbdev compat layer");
+module_param(fbdev, bool, 0600);
+#endif
+
 static char *vram = "16m";
 MODULE_PARM_DESC(vram, "Configure VRAM size (for devices without IOMMU/GPUMMU");
 module_param(vram, charp, 0);
@@ -300,7 +306,8 @@ static int msm_load(struct drm_device *dev, unsigned long flags)
 	drm_mode_config_reset(dev);
 
 #ifdef CONFIG_DRM_MSM_FBDEV
-	priv->fbdev = msm_fbdev_init(dev);
+	if (fbdev)
+		priv->fbdev = msm_fbdev_init(dev);
 #endif
 
 	ret = msm_debugfs_late_init(dev);