powerpc/powernv: Add option CONFIG_POWERNV_MSI

As Michael Ellerman suggested, to add CONFIG_POWERNV_MSI for PowerNV
platform. That's similar to CONFIG_PSERIES_MSI for pSeries platform.
For now, we don't make it dependent on CONFIG_EEH since it's not ready
to enable that yet.

Apart from that, we also enable CONFIG_PPC_MSI_BITMAP on selecting
CONFIG_POWERNV_MSI.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/Kconfig

@@ -8,6 +8,11 @@ config PPC_POWERNV
 	select PPC_PCI_CHOICE if EMBEDDED
 	default y
 
+config POWERNV_MSI
+	bool "Support PCI MSI on PowerNV platform"
+	depends on PCI_MSI
+	default y
+
 config PPC_POWERNV_RTAS
 	depends on PPC_POWERNV
 	bool "Support for RTAS based PowerNV platforms such as BML"

arch/powerpc/sysdev/Kconfig

@@ -19,7 +19,7 @@ config PPC_MSI_BITMAP
 	default y if MPIC
 	default y if FSL_PCI
 	default y if PPC4xx_MSI
-	default y if PPC_POWERNV
+	default y if POWERNV_MSI
 
 source "arch/powerpc/sysdev/xics/Kconfig"