platform/x86: asus-wmi: Move asus_wmi_input_init and _exit lower in the file

Move the asus_wmi_input_init() and asus_wmi_input_exit() functions to
below the WMI helpers, so that further patches in this patch-set can use
the WMI helpers inside asus_wmi_input_init() without needing a forward
declaration.

Note this commit makes no functional changes, the moved block of code
is completely unchanged.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>