powerpc/powernv: Replace CONFIG_POWERNV_MSI with just CONFIG_PPC_POWERNV

We currently have a user visible CONFIG_POWERNV_MSI option, but it
doesn't actually disable MSI for powernv. The MSI code is always built,
what it does disable is the inclusion of the MSI bitmap code, which
leads to a build error.

eg, with PPC_POWERNV=y and POWERNV_MSI=n we get:

  arch/powerpc/platforms/built-in.o: In function `.pnv_teardown_msi_irqs':
  pci.c:(.text+0x3558): undefined reference to `.msi_bitmap_free_hwirqs'

We don't really need a POWERNV_MSI symbol, just have the MSI bitmap code
depend directly on PPC_POWERNV.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Reviewed-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/Kconfig

@@ -13,11 +13,6 @@ config PPC_POWERNV
 	select ARCH_RANDOM
 	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 POWERNV_MSI
+	default y if PPC_POWERNV
 
 source "arch/powerpc/sysdev/xics/Kconfig"