toshiba_acpi: Fix USB Sleep and Music always disabled

Commit e1a949c1 ("toshiba_acpi: Refactor *{get, set} functions return
value") made changes on the return type of the HCI/SCI functions, but a
typo on the USB Sleep and Music code is always reporting non existent
support for such feature.

This patch corrects the typo, changing an assignment to a comparison,
making the laptops with actual support for such feature to work again.

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