According to the datasheet:
BCLK is controlled by BIT[4:2] of WM8940_CLOCK(06h) register.
Signed-off-by: NChris Paulson-Ellis <chris@edesix.com>
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>