Input: wistron_btns - use kmemdup_array instead of kmemdup for multiple allocation

Let the kmemdup_array() take care about multiplication
and possible overflows.

Using kmemdup_array() is more appropriate and makes the code
easier to audit.
Signed-off-by: Shen Lichuan <shenlichuan@vivo.com>
Link: https://lore.kernel.org/r/20240826045253.3503-1-shenlichuan@vivo.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/misc/wistron_btns.c

@@ -990,8 +990,8 @@ static int __init copy_keymap(void)
 	for (key = keymap; key->type != KE_END; key++)
 		length++;
 
-	new_keymap = kmemdup(keymap, length * sizeof(struct key_entry),
-			     GFP_KERNEL);
+	new_keymap = kmemdup_array(keymap, length, sizeof(struct key_entry),
+				   GFP_KERNEL);
 	if (!new_keymap)
 		return -ENOMEM;