drm/bochs: Fix the ID mismatch error

When running RISC-V QEMU with the Bochs device attached via PCIe the
probe of the Bochs device fails with:
    [drm:bochs_hw_init] *ERROR* ID mismatch

This was introduced by this commit:
    7780eb9c bochs: convert to drm_dev_register

To fix the error we ensure that pci_enable_device() is called before
bochs_load().

Fixes: 7780eb9c ("bochs: convert to drm_dev_register")
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reported-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190221003231.31625-1-alistair.francis@wdc.comSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/bochs/bochs_drv.c

@@ -154,6 +154,10 @@ static int bochs_pci_probe(struct pci_dev *pdev,
 	if (IS_ERR(dev))
 		return PTR_ERR(dev);
 
+	ret = pci_enable_device(pdev);
+	if (ret)
+		goto err_free_dev;
+
 	dev->pdev = pdev;
 	pci_set_drvdata(pdev, dev);