ipmi: initialize len variable

Clang static analysis reports this issue
ipmi_ssif.c:1731:3: warning: 4th function call
  argument is an uninitialized value
  dev_info(&ssif_info->client->dev,
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The 4th parameter is the 'len' variable.
len is only set by a successful call to do_cmd().
Initialize to len 0.

Signed-off-by: Tom Rix <trix@redhat.com>
Message-Id: <20220320135954.2258545-1-trix@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Author: Tom Rix

drivers/char/ipmi/ipmi_ssif.c

@@ -1625,7 +1625,7 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	unsigned char     *resp;
 	struct ssif_info   *ssif_info;
 	int               rv = 0;
-	int               len;
+	int               len = 0;
 	int               i;
 	u8		  slave_addr = 0;
 	struct ssif_addr_info *addr_info = NULL;