drm/radeon: make radeon_connector_encoder_is_hbr2 static

It's only used in radeon_connectors.c.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -1512,7 +1512,7 @@ u16 radeon_connector_encoder_get_dp_bridge_encoder_id(struct drm_connector *conn
 	return ENCODER_OBJECT_ID_NONE;
 }
 
-bool radeon_connector_encoder_is_hbr2(struct drm_connector *connector)
+static bool radeon_connector_encoder_is_hbr2(struct drm_connector *connector)
 {
 	struct drm_encoder *encoder;
 	struct radeon_encoder *radeon_encoder;

drivers/gpu/drm/radeon/radeon_mode.h

@@ -685,7 +685,6 @@ extern bool radeon_dig_monitor_is_duallink(struct drm_encoder *encoder,
 
 extern u16 radeon_encoder_get_dp_bridge_encoder_id(struct drm_encoder *encoder);
 extern u16 radeon_connector_encoder_get_dp_bridge_encoder_id(struct drm_connector *connector);
-extern bool radeon_connector_encoder_is_hbr2(struct drm_connector *connector);
 extern bool radeon_connector_is_dp12_capable(struct drm_connector *connector);
 extern int radeon_get_monitor_bpc(struct drm_connector *connector);