irqchip/mbigen: Add ACPI support

With the preparation of platform msi support and interrupt producer
in commit d44fa3d4 ("ACPI: Add support for ResourceSource/IRQ
domain mapping"), we can add mbigen ACPI support now.

Now that the major framework changes are ready, we just need to add
the ACPI probe code which creates the irqdomain for devices connecting
to it.

In order to create the irqdomain, we need to know the number of hw
irqs as input which is provided by mbigen. In DT case, we are using
"num-pins" property to describe it, and we will take advantage of
that too using _DSD in ACPI as there is no standard way of describe
it in ACPI way, also according to the _DSD rule described in
Documentation/acpi/DSD-properties-rules.txt, it doesn't break
the rules.

The DSDT is represented as below:

For mbigen,
  Device(MBI0) {
          Name(_HID, "HISI0152")
          Name(_UID, Zero)
          Name(_CRS, ResourceTemplate() {
                  Memory32Fixed(ReadWrite, 0xa0080000, 0x10000)
          })

         Name(_DSD, Package () {
                 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                 Package () {
                         Package () {"num-pins", 378}
                 }
        })
 }

For devices,
 Device(SAS0) {
         Name(_HID, "HISIxxxx")
         Name(_UID, Zero)
         Name(_CRS, ResourceTemplate() {
                 Memory32Fixed(ReadWrite, 0xb0030000, 0x10000)
		 Interrupt(ResourceConsumer,..., "\_SB.MBI0") {12, ...}
         })
 }

So for the devices connected to the mbigen, as we clearly say that
it refers to a specific interrupt controller (mbigen), we can get
the virq from mbigen's irqdomain once it's created successfully.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: MaJun <majun258@huawei.com>
Cc: Al Stone <ahs3@redhat.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>