irqchip/loongson-eiointc: Fix return value checking of eiointc_index

Return value of function eiointc_index is int, however it is converted
into uint32_t and then compared smaller than zero, this will cause logic
problem.

Fixes: dd281e1 ("irqchip: Add Loongson Extended I/O interrupt controller support")
Signed-off-by: Bibo Mao <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: bibo-mao

drivers/irqchip/irq-loongson-eiointc.c

@@ -144,7 +144,7 @@ static int eiointc_router_init(unsigned int cpu)
 	int i, bit;
 	uint32_t data;
 	uint32_t node = cpu_to_eio_node(cpu);
-	uint32_t index = eiointc_index(node);
+	int index = eiointc_index(node);
 
 	if (index < 0) {
 		pr_err("Error: invalid nodemap!\n");