drm/cirrus/ast/mgag200: fix build without CONFIG_VGA_CONSOLE

Reported-by: Randy Dunlap
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index b56eac6..d0c4574 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -221,8 +221,10 @@
 
 static int __init ast_init(void)
 {
+#ifdef CONFIG_VGA_CONSOLE
 	if (vgacon_text_force() && ast_modeset == -1)
 		return -EINVAL;
+#endif
 
 	if (ast_modeset == 0)
 		return -EINVAL;