irqchip/ls-scfg-msi: Add LS1043a v1.1 MSI support

A MSI controller of LS1043a v1.0 only includes one MSIR and
is assigned one GIC interrupt. In order to support affinity,
LS1043a v1.1 MSI is assigned 4 MSIRs and 4 GIC interrupts.
But the MSIR has the different offset and only supports 8 MSIs.
The bits between variable bit_start and bit_end in structure
ls_scfg_msir are used to show 8 MSI interrupts. msir_irqs and
msir_base are added to describe the difference of MSI between
LS1043a v1.1 and other SoCs.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Minghuan Lian <Minghuan.Lian@nxp.com>
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>