hwmon: (ina2xx) Fix access to uninitialized mutex

BugLink: http://bugs.launchpad.net/bugs/1768429

commit 0c4c5860 upstream.

Initialize data->config_lock mutex before it is used by the driver code.

This fixes following warning on Odroid XU3 boards:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc7-next-20180115-00001-gb75575dee3f2 #107
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[<c0111504>] (unwind_backtrace) from [<c010dbec>] (show_stack+0x10/0x14)
[<c010dbec>] (show_stack) from [<c09b3f74>] (dump_stack+0x90/0xc8)
[<c09b3f74>] (dump_stack) from [<c0179528>] (register_lock_class+0x1c0/0x59c)
[<c0179528>] (register_lock_class) from [<c017bd1c>] (__lock_acquire+0x78/0x1850)
[<c017bd1c>] (__lock_acquire) from [<c017de30>] (lock_acquire+0xc8/0x2b8)
[<c017de30>] (lock_acquire) from [<c09ca59c>] (__mutex_lock+0x60/0xa0c)
[<c09ca59c>] (__mutex_lock) from [<c09cafd0>] (mutex_lock_nested+0x1c/0x24)
[<c09cafd0>] (mutex_lock_nested) from [<c068b0d0>] (ina2xx_set_shunt+0x70/0xb0)
[<c068b0d0>] (ina2xx_set_shunt) from [<c068b218>] (ina2xx_probe+0x88/0x1b0)
[<c068b218>] (ina2xx_probe) from [<c0673d90>] (i2c_device_probe+0x1e0/0x2d0)
[<c0673d90>] (i2c_device_probe) from [<c053a268>] (driver_probe_device+0x2b8/0x4a0)
[<c053a268>] (driver_probe_device) from [<c053a54c>] (__driver_attach+0xfc/0x120)
[<c053a54c>] (__driver_attach) from [<c05384cc>] (bus_for_each_dev+0x58/0x7c)
[<c05384cc>] (bus_for_each_dev) from [<c0539590>] (bus_add_driver+0x174/0x250)
[<c0539590>] (bus_add_driver) from [<c053b5e0>] (driver_register+0x78/0xf4)
[<c053b5e0>] (driver_register) from [<c0675ef0>] (i2c_register_driver+0x38/0xa8)
[<c0675ef0>] (i2c_register_driver) from [<c0102b40>] (do_one_initcall+0x48/0x18c)
[<c0102b40>] (do_one_initcall) from [<c0e00df0>] (kernel_init_freeable+0x110/0x1d4)
[<c0e00df0>] (kernel_init_freeable) from [<c09c8120>] (kernel_init+0x8/0x114)
[<c09c8120>] (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20)

Fixes: 5d389b12 ("hwmon: (ina2xx) Make calibration register value fixed")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
[backport to v4.4.y/v4.9.y: context changes]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/hwmon/ina2xx.c

@@ -447,6 +447,7 @@ static int ina2xx_probe(struct i2c_client *client,
 
 	/* set the device type */
 	data->config = &ina2xx_config[id->driver_data];
+	mutex_init(&data->config_lock);
 
 	if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
 		struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
@@ -473,8 +474,6 @@ static int ina2xx_probe(struct i2c_client *client,
 		return -ENODEV;
 	}
 
-	mutex_init(&data->config_lock);
-
 	data->groups[group++] = &ina2xx_group;
 	if (id->driver_data == ina226)
 		data->groups[group++] = &ina226_group;