toshiba_acpi: Move hotkey enabling code to its own function

The hotkey enabling code is being used by *_setup_keyboard and also by
*_resume.

This patch creates a new function called toshiba_acpi_enable_hotkeys to
be used by these two functions to avoid duplicating code.

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