mimxrt10xx: Factor out "transfer_common"
mimxrt10xx: Factor out "transfer_common"

.. and set the "MasterPcsContinuous" flag, which removes some of the
gap between bytes of a single SPI transaction

adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython