hw/riscv/sifive_plic: Use gpios instead of irqs

Instead of creating the interrupt in lines with qemu_allocate_irq() use
qdev_init_gpio_in() as this gives us the ability to use the qdev*gpio*()
helpers later on.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Suggested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Michael Clark <mjc@sifive.com>

include/hw/riscv/sifive_plic.h

@@ -56,7 +56,6 @@ typedef struct SiFivePLICState {
     uint32_t *claimed;
     uint32_t *enable;
     QemuMutex lock;
-    qemu_irq *irqs;
 
     /* config */
     char *hart_config;