toshiba_acpi: Add support for USB Rapid Charge

Newer Toshiba laptops equipped with USB 3.0 ports now have the
functionality of rapid charging devices connected to their USB hubs.

This patch adds support to use such feature by creating a sysfs entry
named "usb_rapid_charge", accepting only two values, 0 to disable and
1 to enable, however, the machine needs a restart everytime the
function is toggled.

Signed-off-by: Azael Avalos <coproscefalo@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>