irqchip/s3c24xx: Remove unneeded comparison of unsigned long to 0

irq_data->hwirq is unsigned long.  This fixes GCC warning:

    drivers/irqchip/irq-s3c24xx.c: In function 's3c_irqext0_type':
    drivers/irqchip/irq-s3c24xx.c:253:19: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
      if ((data->hwirq >= 0) && (data->hwirq <= 3)) {
                       ^~

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-s3c24xx.c

@@ -250,7 +250,7 @@ static int s3c_irqext0_type(struct irq_data *data, unsigned int type)
 	void __iomem *gpcon_reg;
 	unsigned long gpcon_offset, extint_offset;
 
-	if ((data->hwirq >= 0) && (data->hwirq <= 3)) {
+	if (data->hwirq <= 3) {
 		gpcon_reg = S3C2410_GPFCON;
 		extint_reg = S3C24XX_EXTINT0;
 		gpcon_offset = (data->hwirq) * 2;