usb: Only disable HID devices if both USB_MOUSE and USB_KEYBOARD are off.

Fix typo in code causing both CONFIG_USB_MOUSE and CONFIG_USB_KEYBOARD
to be effectively disabled if either is disabled.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Minor - fix some typos in comments.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>