dma: tegra20-apb-dma: Staticize tegra_dma_prep_dma_cyclic

tegra_dma_prep_dma_cyclic is referenced only in this file.
Make it static.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/tegra20-apb-dma.c

@@ -1018,7 +1018,7 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
 	return &dma_desc->txd;
 }
 
-struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
+static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
 	struct dma_chan *dc, dma_addr_t buf_addr, size_t buf_len,
 	size_t period_len, enum dma_transfer_direction direction,
 	unsigned long flags, void *context)