forked from Mirrors/opensbi

The number of interrupt enable register in words was once correct, but was wrongly changed to have an off-by-one error since commit8c362e7d06
("lib: irqchip/plic: Factor out a context init function"). Fixes:8c362e7d06
("lib: irqchip/plic: Factor out a context init function") Signed-off-by: Bin Meng <bmeng@tinylab.org> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Samuel Holland <samuel@sholland.org>