dmaengine: sort the dw Kconfig

Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dw/Kconfig

@@ -6,6 +6,9 @@ config DW_DMAC_CORE
 	tristate
 	select DMA_ENGINE
 
+config DW_DMAC_BIG_ENDIAN_IO
+	bool
+
 config DW_DMAC
 	tristate "Synopsys DesignWare AHB DMA platform driver"
 	select DW_DMAC_CORE
@@ -23,6 +26,3 @@ config DW_DMAC_PCI
 	  Support the Synopsys DesignWare AHB DMA controller on the
 	  platfroms that enumerate it as a PCI device. For example,
 	  Intel Medfield has integrated this GPDMA controller.
-
-config DW_DMAC_BIG_ENDIAN_IO
-	bool