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>

drivers/platform/x86/toshiba_acpi.c

@@ -938,7 +938,7 @@ static int toshiba_usb_sleep_music_get(struct toshiba_acpi_dev *dev, u32 *state)
 	else if (result == TOS_NOT_SUPPORTED)
 		return -ENODEV;
 
-	return result = TOS_SUCCESS ? 0 : -EIO;
+	return result == TOS_SUCCESS ? 0 : -EIO;
 }
 
 static int toshiba_usb_sleep_music_set(struct toshiba_acpi_dev *dev, u32 state)