drm/amd/display: add missing void parameter to dc_create_transfer_func

Add a missing void parameter to function dc_create_transfer_func, fixes
sparse warning:

warning: non-ANSI function declaration of function 'dc_create_transfer_func'
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_surface.c

@@ -192,7 +192,7 @@ void dc_transfer_func_release(struct dc_transfer_func *tf)
 	kref_put(&tf->refcount, dc_transfer_func_free);
 }
 
-struct dc_transfer_func *dc_create_transfer_func()
+struct dc_transfer_func *dc_create_transfer_func(void)
 {
 	struct dc_transfer_func *tf = kvzalloc(sizeof(*tf), GFP_KERNEL);