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 <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/gma500/psb_drv.c

@@ -52,7 +52,7 @@ module_param_named(trap_pagefaults, drm_psb_trap_pagefaults, int, 0600);
 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},