gma500: Final enables for Oaktrail

This switches the ifdef to match the Kconfig so that Oaktrail probing occurs
and adds some additional minor bulletproofing.

Tested on a Fujtisu Stylistic Q550 internal display. HDMI might work but that
remains to be seen.

Signed-off-by: Alan Cox <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/gma500/mid_bios.c

···
 #define FB_SKU_100 0
 #define FB_SKU_100L 1
 #define FB_SKU_83 2
+	if (pci_root == NULL) {
+		WARN_ON(1);
+		return;
+	}
+
+
 	pci_write_config_dword(pci_root, 0xD0, FB_REG06);
 	pci_read_config_dword(pci_root, 0xD4, &fuse_value);
 
···
 	uint32_t platform_rev_id = 0;
 	struct pci_dev *pci_gfx_root = pci_get_bus_and_slot(0, PCI_DEVFN(2, 0));
 
+	if (pci_gfx_root == NULL) {
+		WARN_ON(1);
+		return;
+	}
 	pci_read_config_dword(pci_gfx_root, 0x08, &platform_rev_id);
 	dev_priv->platform_rev_id = (uint8_t) platform_rev_id;
 	pci_dev_put(pci_gfx_root);
···
 
 	/* get the virtual address of the vbt */
 	vbt_virtual = ioremap(addr, sizeof(*vbt));
+	if (vbt_virtual == NULL) {
+		vbt->size = 0;
+		return;
+	}
 
 	memcpy(vbt, vbt_virtual, sizeof(*vbt));
 	iounmap(vbt_virtual); /* Free virtual address space */

drivers/gpu/drm/gma500/psb_drv.c

···
 static DEFINE_PCI_DEVICE_TABLE(pciidlist) = {
 	{ 0x8086, 0x8108, PCI_ANY_ID, PCI_ANY_ID, 0, 0, (long) &psb_chip_ops },
 	{ 0x8086, 0x8109, PCI_ANY_ID, PCI_ANY_ID, 0, 0, (long) &psb_chip_ops },
-#if defined(CONFIG_DRM_OAKTRAIL)
+#if defined(CONFIG_DRM_GMA600)
 	{ 0x8086, 0x4100, PCI_ANY_ID, PCI_ANY_ID, 0, 0, (long) &oaktrail_chip_ops},
 	{ 0x8086, 0x4101, PCI_ANY_ID, PCI_ANY_ID, 0, 0, (long) &oaktrail_chip_ops},
 	{ 0x8086, 0x4102, PCI_ANY_ID, PCI_ANY_ID, 0, 0, (long) &oaktrail_chip_ops},