ipmi_si: Fix wrong return value in try_smi_init()

On an error exit path, a negative error code should be returned
instead of a positive return value.

Fixes: 90b2d4f1 ("ipmi_si: Remove hacks for adding a dummy platform devices")
Cc: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Message-Id: <20201005145212.84435-1-tianjia.zhang@linux.alibaba.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_si_intf.c

@@ -1980,7 +1980,7 @@ static int try_smi_init(struct smi_info *new_smi)
 	/* Do this early so it's available for logs. */
 	if (!new_smi->io.dev) {
 		pr_err("IPMI interface added with no device\n");
-		rv = EIO;
+		rv = -EIO;
 		goto out_err;
 	}