forked from Mirrors/opensbi
		
	We add simple IMSIC library which is independent of hardware description format (FDT or ACPI). This IMSIC library can be used by custom OpenSBI platform support to setup IMSIC for external interrupts. Signed-off-by: Anup Patel <anup.patel@wdc.com> Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com>