Fix uninitialized variable in ipmb_dev_int.c

ret at line 112 of ipmb_dev_int.c is uninitialized which
results in a warning during build regressions.
This warning was found by build regression/improvement
testing for v5.3-rc1.

Reported-by: build regression/improvement testing for v5.3-rc1.
Fixes: 51bd6f29 ("Add support for IPMB driver")
Signed-off-by: Asmaa Mnebhi <Asmaa@mellanox.com>
Message-Id: <571dbb67cf58411d567953d9fb3739eb4789238b.1563996586.git.Asmaa@mellanox.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmb_dev_int.c

@@ -76,7 +76,7 @@ static ssize_t ipmb_read(struct file *file, char __user *buf, size_t count,
 	struct ipmb_dev *ipmb_dev = to_ipmb_dev(file);
 	struct ipmb_request_elem *queue_elem;
 	struct ipmb_msg msg;
-	ssize_t ret;
+	ssize_t ret = 0;
 
 	memset(&msg, 0, sizeof(msg));