riscv: plic: Honour source priorities
The source priorities can be used to order sources with respect to other
sources, not just as a way to enable/disable them based off a threshold.
We must therefore always claim the highest-priority source, rather than
the first source we find.
Signed-off-by: Jessica Clarke <jrtc27@jrtc27.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <
20200618202343.20455-1-jrtc27@jrtc27.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>