i2c: cp2615: replace deprecated strncpy with strscpy

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We should prefer more robust and less ambiguous string interfaces.

We expect name to be NUL-terminated based on its numerous uses with
functions that expect NUL-terminated strings.

For example in i2c-core-base.c +1533:
| dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);

NUL-padding is not required as `adap` is already zero-alloacted with:
| adap = devm_kzalloc(&usbif->dev, sizeof(struct i2c_adapter), GFP_KERNEL);

With the above in mind, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: KSPP#90
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Author: JustinStitt

drivers/i2c/busses/i2c-cp2615.c

@@ -298,7 +298,7 @@ cp2615_i2c_probe(struct usb_interface *usbif, const struct usb_device_id *id)
 	if (!adap)
 		return -ENOMEM;
 
-	strncpy(adap->name, usbdev->serial, sizeof(adap->name) - 1);
+	strscpy(adap->name, usbdev->serial, sizeof(adap->name));
 	adap->owner = THIS_MODULE;
 	adap->dev.parent = &usbif->dev;
 	adap->dev.of_node = usbif->dev.of_node;