x86/PCI: make Broadcom CNB20LE driver EMBEDDED and EXPERIMENTAL

This functionality is known to be incomplete, so discourage its use in
general-purpose kernels.

The only reason to use this driver is to support PCI hotplug on CNB20LE-
based machines that don't have ACPI, and there are very few such
systems.

Reference: https://bugzilla.redhat.com/show_bug.cgi?id=665109
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

arch/x86/Kconfig

@@ -1907,13 +1907,19 @@ config PCI_MMCONFIG
 	depends on X86_64 && PCI && ACPI
 
 config PCI_CNB20LE_QUIRK
-	bool "Read CNB20LE Host Bridge Windows"
-	depends on PCI
+	bool "Read CNB20LE Host Bridge Windows" if EMBEDDED
+	default n
+	depends on PCI && EXPERIMENTAL
 	help
 	  Read the PCI windows out of the CNB20LE host bridge. This allows
 	  PCI hotplug to work on systems with the CNB20LE chipset which do
 	  not have ACPI.
 
+	  There's no public spec for this chipset, and this functionality
+	  is known to be incomplete.
+
+	  You should say N unless you know you need this.
+
 config DMAR
 	bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
 	depends on PCI_MSI && ACPI && EXPERIMENTAL