forked from Mirrors/opensbi

Currently, the external interrupt handling is scattered between sbi_init and sbi_trap. This patch moves all external interrupt handling into a simple framework called sbi_irqchip. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Xiang W <wxjstz@126.com> Reviewed-by: Atish Patra <atishp@rivosinc.com>