phy: mediatek: add a new helper to update bitfield

Due to FIELD_PREP() macro can be used to prepare a bitfield value,
local ones can be remove; add the new helper to make bitfield update
easier.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20220920090038.15133-2-chunfeng.yun@mediatek.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/mediatek/phy-mtk-io.h

@@ -8,6 +8,7 @@
 #ifndef __PHY_MTK_H__
 #define __PHY_MTK_H__
 
+#include <linux/bitfield.h>
 #include <linux/io.h>
 
 static inline void mtk_phy_clear_bits(void __iomem *reg, u32 bits)
@@ -35,4 +36,10 @@ static inline void mtk_phy_update_bits(void __iomem *reg, u32 mask, u32 val)
 	writel(tmp, reg);
 }
 
+/* field @mask should be constant and continuous */
+static inline void mtk_phy_update_field(void __iomem *reg, u32 mask, u32 val)
+{
+	mtk_phy_update_bits(reg, mask, FIELD_PREP(mask, val));
+}
+
 #endif