dmaengine: moxart: fix kconfig unmet direct dependencies

We have unmet direct dependencies as DMA_SUN4I selects DMA_OF so remove the
selection

warning: (DMA_SUN4I && MOXART_DMA && STM32_DMA) selects DMA_OF which has
unmet direct dependencies (DMADEVICES && OF)
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/Kconfig

@@ -315,7 +315,6 @@ config MOXART_DMA
 	tristate "MOXART DMA support"
 	depends on ARCH_MOXART
 	select DMA_ENGINE
-	select DMA_OF
 	select DMA_VIRTUAL_CHANNELS
 	help
 	  Enable support for the MOXA ART SoC DMA controller.