dmaengine: make mux_configure32 static

There is one sparse warning in drivers/dma/fsl-edma-common.c:
drivers/dma/fsl-edma-common.c:93:6: warning: symbol 'mux_configure32'
was not declared. Should it be static?

Fix it by setting mux_configure32() as static.

Fixes: 232a7f18 ("dmaengine: fsl-edma: add i.mx7ulp edma2 version support")
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Link: https://lore.kernel.org/r/20190814072105.144107-2-maowenan@huawei.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/fsl-edma-common.c

@@ -90,7 +90,7 @@ static void mux_configure8(struct fsl_edma_chan *fsl_chan, void __iomem *addr,
 	iowrite8(val8, addr + off);
 }
 
-void mux_configure32(struct fsl_edma_chan *fsl_chan, void __iomem *addr,
+static void mux_configure32(struct fsl_edma_chan *fsl_chan, void __iomem *addr,
 		     u32 off, u32 slot, bool enable)
 {
 	u32 val;