irqchip/gic-v3-its: Allow GIC ITS number more than MAX_NUMNODES

irqchip/gic-v3-its: Allow GIC ITS number more than MAX_NUMNODES

When enabling ITS NUMA support on D05, I got the boot log:

[    0.000000] SRAT: PXM 0 -> ITS 0 -> Node 0
[    0.000000] SRAT: PXM 0 -> ITS 1 -> Node 0
[    0.000000] SRAT: PXM 0 -> ITS 2 -> Node 0
[    0.000000] SRAT: PXM 1 -> ITS 3 -> Node 1
[    0.000000] SRAT: ITS affinity exceeding max count[4]

This is wrong on D05 as we have 8 ITSs with 4 NUMA nodes.

So dynamically alloc the memory needed instead of using
its_srat_maps[MAX_NUMNODES], which count the number of
ITS entry(ies) in SRAT and alloc its_srat_maps as needed,
then build the mapping of numa node to ITS ID. Of course,
its_srat_maps will be freed after ITS probing because
we don't need that after boot.

After doing this, I got what I wanted:

[    0.000000] SRAT: PXM 0 -> ITS 0 -> Node 0
[    0.000000] SRAT: PXM 0 -> ITS 1 -> Node 0
[    0.000000] SRAT: PXM 0 -> ITS 2 -> Node 0
[    0.000000] SRAT: PXM 1 -> ITS 3 -> Node 1
[    0.000000] SRAT: PXM 2 -> ITS 4 -> Node 2
[    0.000000] SRAT: PXM 2 -> ITS 5 -> Node 2
[    0.000000] SRAT: PXM 2 -> ITS 6 -> Node 2
[    0.000000] SRAT: PXM 3 -> ITS 7 -> Node 3

Fixes: dbd2b8267233 ("irqchip/gic-v3-its: Add ACPI NUMA node mapping")
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Cc: John Garry <john.garry@huawei.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>