spi: sun4i: Simplify reg writes using set/clrbits_le32

Update the existing register writes using setbits_le32 and
clrbits_le32 in required places.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/spi/sun4i_spi.c b/drivers/spi/sun4i_spi.c
index f5f2d56..0b16630 100644
--- a/drivers/spi/sun4i_spi.c
+++ b/drivers/spi/sun4i_spi.c
@@ -283,20 +283,18 @@
 {
 	struct sun4i_spi_priv *priv = dev_get_priv(dev->parent);
 
-	writel(SUN4I_CTL_ENABLE | SUN4I_CTL_MASTER | SUN4I_CTL_TP |
-	       SUN4I_CTL_CS_MANUAL | SUN4I_CTL_CS_ACTIVE_LOW,
-	       &priv->regs->ctl);
+	setbits_le32(&priv->regs->ctl, SUN4I_CTL_ENABLE |
+		     SUN4I_CTL_MASTER | SUN4I_CTL_TP |
+		     SUN4I_CTL_CS_MANUAL | SUN4I_CTL_CS_ACTIVE_LOW);
+
 	return 0;
 }
 
 static int sun4i_spi_release_bus(struct udevice *dev)
 {
 	struct sun4i_spi_priv *priv = dev_get_priv(dev->parent);
-	u32 reg;
 
-	reg = readl(&priv->regs->ctl);
-	reg &= ~SUN4I_CTL_ENABLE;
-	writel(reg, &priv->regs->ctl);
+	clrbits_le32(&priv->regs->ctl, SUN4I_CTL_ENABLE);
 
 	return 0;
 }
@@ -309,7 +307,7 @@
 	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
 
 	u32 len = bitlen / 8;
-	u32 reg, rx_fifocnt;
+	u32 rx_fifocnt;
 	u8 nbytes;
 	int ret;
 
@@ -324,10 +322,8 @@
 	if (flags & SPI_XFER_BEGIN)
 		sun4i_spi_set_cs(bus, slave_plat->cs, true);
 
-	reg = readl(&priv->regs->ctl);
-
 	/* Reset FIFOs */
-	writel(reg | SUN4I_CTL_RF_RST | SUN4I_CTL_TF_RST, &priv->regs->ctl);
+	setbits_le32(&priv->regs->ctl, SUN4I_CTL_RF_RST | SUN4I_CTL_TF_RST);
 
 	while (len) {
 		/* Setup the transfer now... */
@@ -341,8 +337,7 @@
 		sun4i_spi_fill_fifo(priv, nbytes);
 
 		/* Start the transfer */
-		reg = readl(&priv->regs->ctl);
-		writel(reg | SUN4I_CTL_XCH, &priv->regs->ctl);
+		setbits_le32(&priv->regs->ctl, SUN4I_CTL_XCH);
 
 		/* Wait till RX FIFO to be empty */
 		ret = readl_poll_timeout(&priv->regs->fifo_sta, rx_fifocnt,