ARM64/irqchip: Update ACPI_IORT symbol selection logic

ACPI IORT is an ACPI addendum to describe the connection topology of
devices with IOMMUs and interrupt controllers on ARM64 ACPI systems.

Currently the ACPI IORT Kbuild symbol is selected whenever the Kbuild
symbol ARM_GIC_V3_ITS is enabled, which in turn is selected by ARM64
Kbuild defaults. This makes the logic behind ACPI_IORT selection a bit
twisted and not easy to follow. On ARM64 systems enabling ACPI the
kbuild symbol ACPI_IORT should always be selected in that it is a kernel
layer provided to the ARM64 arch code to parse and enable ACPI firmware
bindings.

Make the ACPI_IORT selection explicit in ARM64 Kbuild and remove the
selection from ARM_GIC_V3_ITS entry, making the ACPI_IORT selection
logic clearer to follow.
Acked-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/Kconfig

@@ -3,6 +3,7 @@ config ARM64
 	select ACPI_CCA_REQUIRED if ACPI
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_GTDT if ACPI
+	select ACPI_IORT if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
 	select ACPI_MCFG if ACPI
 	select ACPI_SPCR_TABLE if ACPI

drivers/irqchip/Kconfig

@@ -39,7 +39,6 @@ config ARM_GIC_V3_ITS
 	bool
 	depends on PCI
 	depends on PCI_MSI
-	select ACPI_IORT if ACPI
 
 config ARM_NVIC
 	bool