There is a bug in the ps7 component specification that causes critical
warnings to appear in the build log if DMA interface 0 is disabled, but any
other DMA interface is enabled.
Work around this issue by using DMA interface 0 and 1 instead of 1 and 2
for the I2S DMA.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>