Input: serio_raw - fix uninitialized variable bug

Recent conversion of the driver to use guard notation for locks and
other resources introduced a bug: "written" variable that is supposed to
hold number of bytes successfully written was not initialized.

Fix it by initializing the variable with 0.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Fixes: 5b53a9d ("Input: serio_raw - use guard notation for locks and other resources")
Signed-off-by: Dmitry Torokhov <[email protected]>

Author: dtor

drivers/input/serio/serio_raw.c

@@ -185,7 +185,7 @@ static ssize_t serio_raw_write(struct file *file, const char __user *buffer,
 {
 	struct serio_raw_client *client = file->private_data;
 	struct serio_raw *serio_raw = client->serio_raw;
-	int written;
+	int written = 0;
 	unsigned char c;
 
 	scoped_guard(mutex_intr, &serio_raw_mutex) {