irqchip/riscv-imsic: Add ACPI support

RISC-V IMSIC interrupt controller provides IPI and MSI support.
Currently, DT based drivers setup the IPI feature early during boot but
defer setting up the MSI functionality. However, in ACPI systems, PCI
subsystem is probed early and assume MSI controller is already setup.
Hence, both IPI and MSI features need to be initialized early itself.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20240812005929.113499-16-sunilvl@ventanamicro.com


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>