avr32: at32ap700x: fix typo in DMA master configuration

avr32: at32ap700x: fix typo in DMA master configuration

Commit 4aa5f366431fe (avr32: at32ap700x: specify DMA src and dst
masters) specified the masters for the ac97c playback device
but incorrectly set them in the capture slave information rather
than playback.

Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Reported-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
[rebased on dmaengine for 2.6.39 (d42efe6b)]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>