ACPI, x86: fix Dell M6600 ACPI reboot regression via DMI

Dell Precision M6600 is known to require PCI reboot, so add it to
the reboot blacklist in pci_reboot_dmi_table[].

https://bugzilla.kernel.org/show_bug.cgi?id=42749

cc: x86@kernel.org
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

arch/x86/kernel/reboot.c

@@ -451,6 +451,14 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
 		},
 	},
+	{	/* Handle problems with rebooting on the Precision M6600. */
+		.callback = set_pci_reboot,
+		.ident = "Dell OptiPlex 990",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
+		},
+	},
 	{ }
 };