ASoC: blackfin: Switch bf5xx-ad1836 from bf5xx-tdm to bf5xx-i2s

The bf5xx-i2s driver now has support for TDM mode and the bf5xx-tdm driver is
going to be removed soon, so switch the driver over to bf5xx-i2s.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>