PN532_SPI._wait_ready cannot recover if failing

[basil-huber]

PN532_SPI._wait_ready polls the status until ready. However, the command to be sent is overwritten by the response received. Hence, if the device is not ready at the first request, we might send the wrong command for subsequent polling:

while (time.monotonic() - timestamp) < timeout:
                time.sleep(0.02)   # required
                spi.write_readinto(status, status) #pylint: disable=no-member
                if reverse_bit(status[1]) == 0x01:  # LSB data is read in MSB
                    return True      # Not busy anymore!
                else:
                    time.sleep(0.01)  # pause a bit till we ask again

the command in status is overwritten.