dmaengine: fsl-edma-common: move dmamux register to another single function

Prepare for edmav2 on i.mx7ulp whose dmamux register is 32bit. No function
impacted.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Tested-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/fsl-edma-common.c

@@ -77,6 +77,19 @@ void fsl_edma_disable_request(struct fsl_edma_chan *fsl_chan)
 }
 EXPORT_SYMBOL_GPL(fsl_edma_disable_request);
 
+static void mux_configure8(struct fsl_edma_chan *fsl_chan, void __iomem *addr,
+			   u32 off, u32 slot, bool enable)
+{
+	u8 val8;
+
+	if (enable)
+		val8 = EDMAMUX_CHCFG_ENBL | slot;
+	else
+		val8 = EDMAMUX_CHCFG_DIS;
+
+	iowrite8(val8, addr + off);
+}
+
 void fsl_edma_chan_mux(struct fsl_edma_chan *fsl_chan,
 			unsigned int slot, bool enable)
 {
@@ -90,10 +103,7 @@ void fsl_edma_chan_mux(struct fsl_edma_chan *fsl_chan,
 	muxaddr = fsl_chan->edma->muxbase[ch / chans_per_mux];
 	slot = EDMAMUX_CHCFG_SOURCE(slot);
 
-	if (enable)
-		iowrite8(EDMAMUX_CHCFG_ENBL | slot, muxaddr + ch_off);
-	else
-		iowrite8(EDMAMUX_CHCFG_DIS, muxaddr + ch_off);
+	mux_configure8(fsl_chan, muxaddr, ch_off, slot, enable);
 }
 EXPORT_SYMBOL_GPL(fsl_edma_chan_mux);