Bluetooth: btusb, hci_intel: Fix wait_on_bit_timeout() return value checks

wait_on_bit_timeout() returns one of the following three values:
* 0 to indicate success.
* -EINTR to indicate that a signal has been received;
* -EAGAIN to indicate timeout;
Make the wait_on_bit_timeout() callers check for these values.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>