platform/x86: thinkpad_acpi: Remove "goto err_exit" from hotkey_init()

The err_exit label just does a:
 return (res < 0) ? res : -ENODEV;

And res is always < 0 when we go there (hotkey_mask_get() returns
either 0 or -EIO), so the goto-s can simply be replaced with
"return res".

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Mark Pearson <mpearson@lenovo.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211121191129.256713-7-hdegoede@redhat.com