drivers: gpu: Mark functions as static in mgag200_mode.c

Mark functions mga_set_start_address(), mga_encoder_destroy() and
mga_connector_best_encoder() as static in drm/mgag200/mgag200_mode.c
because they are not used outside this file.

This eliminates the following warnings in drm/mgag200/mgag200_mode.c:
drivers/gpu/drm/mgag200/mgag200_mode.c:694:6: warning: no previous
prototype for ‘mga_set_start_address’ [-Wmissing-prototypes]
drivers/gpu/drm/mgag200/mgag200_mode.c:1401:6: warning: no previous
prototype for ‘mga_encoder_destroy’ [-Wmissing-prototypes]
drivers/gpu/drm/mgag200/mgag200_mode.c:1561:21: warning: no previous
prototype for ‘mga_connector_best_encoder’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/mgag200/mgag200_mode.c

@@ -691,7 +691,7 @@ static void mga_g200wb_commit(struct drm_crtc *crtc)
    CRTCEXT0 has to be programmed last to trigger an update and make the
    new addr variable take effect.
  */
-void mga_set_start_address(struct drm_crtc *crtc, unsigned offset)
+static void mga_set_start_address(struct drm_crtc *crtc, unsigned offset)
 {
 	struct mga_device *mdev = crtc->dev->dev_private;
 	u32 addr;
@@ -1398,7 +1398,7 @@ static void mga_encoder_commit(struct drm_encoder *encoder)
 {
 }
 
-void mga_encoder_destroy(struct drm_encoder *encoder)
+static void mga_encoder_destroy(struct drm_encoder *encoder)
 {
 	struct mga_encoder *mga_encoder = to_mga_encoder(encoder);
 	drm_encoder_cleanup(encoder);
@@ -1558,7 +1558,7 @@ static int mga_vga_mode_valid(struct drm_connector *connector,
 	return MODE_OK;
 }
 
-struct drm_encoder *mga_connector_best_encoder(struct drm_connector
+static struct drm_encoder *mga_connector_best_encoder(struct drm_connector
 						  *connector)
 {
 	int enc_id = connector->encoder_ids[0];