x86: pci: Don't return a vesa mode when there is not video

If the video has not been set up, we should not return a success code. This
can be detected by seeing if any of the variables are non-zero.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pci/pci_rom.c b/drivers/pci/pci_rom.c
index af6a3ae..9808bb3 100644
--- a/drivers/pci/pci_rom.c
+++ b/drivers/pci/pci_rom.c
@@ -205,7 +205,7 @@
 	gdev->vprBase = vesa->phys_base_ptr;
 	gdev->cprBase = vesa->phys_base_ptr;
 
-	return 0;
+	return gdev->winSizeX ? 0 : -ENOSYS;
 #else
 	return -ENOSYS;
 #endif