mmc: sh_mobile_sdhi: fix error return code in sh_mobile_sdhi_probe()

Fix to return a negative error code instead of 0 when we cannot get
IRQ source by platform_get_irq(), as done elsewhere in this function.

Signed-off-by: Wei Yongjun <[e-mail]>
Acked-by: Guennadi Liakhovetski <[e-mail]>
Signed-off-by: Chris Ball <[e-mail]>

drivers/mmc/host/sh_mobile_sdhi.c

···
 		}
 
 		/* There must be at least one IRQ source */
-		if (!i)
+		if (!i) {
+			ret = irq;
 			goto eirq;
+		}
 	}
 
 	dev_info(&pdev->dev, "%s base at 0x%08lx clock rate %u MHz\n",