dma/imx-sdma: move clk_enable out of sdma_request_channel

It makes clk_enable/disable pair more readable, and fix one bug:
sdma_init calls sdma_request_channel, but seems don't know
sdma_request_channel enabled the clock.
Signed-off-by: Richard Zhao <richard.zhao@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
[fixed typo in commit log]
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

drivers/dma/imx-sdma.c

@@ -802,8 +802,6 @@ static int sdma_request_channel(struct sdma_channel *sdmac)
 	sdma->channel_control[channel].base_bd_ptr = sdmac->bd_phys;
 	sdma->channel_control[channel].current_bd_ptr = sdmac->bd_phys;
 
-	clk_enable(sdma->clk);
-
 	sdma_set_channel_priority(sdmac, MXC_SDMA_DEFAULT_PRIORITY);
 
 	init_completion(&sdmac->done);
@@ -873,6 +871,9 @@ static int sdma_alloc_chan_resources(struct dma_chan *chan)
 
 	sdmac->peripheral_type = data->peripheral_type;
 	sdmac->event_id0 = data->dma_request;
+
+	clk_enable(sdmac->sdma->clk);
+
 	ret = sdma_request_channel(sdmac);
 	if (ret)
 		return ret;