drm: bump DRM_CONNECTOR_MAX_ENCODER from 2 to 3

There exists at least one NVIDIA GPU (Quadro NVS 300) that has a DMS-59
connector which is capable of supporting DisplayPort, TMDS and VGA on
a single connector.

We need to bump the allowed encoder limit to support all three configs.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

include/drm/drm_crtc.h

@@ -453,7 +453,7 @@ struct drm_encoder_funcs {
 #define DRM_CONNECTOR_MAX_UMODES 16
 #define DRM_CONNECTOR_MAX_PROPERTY 16
 #define DRM_CONNECTOR_LEN 32
-#define DRM_CONNECTOR_MAX_ENCODER 2
+#define DRM_CONNECTOR_MAX_ENCODER 3
 
 /**
  * drm_encoder - central DRM encoder structure