scsi: ufs-mediatek: use common delay function

A common delay function is introduced in UFS core driver, thus ufs-mediatek
can use it instead of the private delay function.

Link: https://lore.kernel.org/r/20200318104016.28049-5-stanley.chu@mediatek.comReviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-mediatek.c

@@ -100,17 +100,6 @@ static int ufs_mtk_bind_mphy(struct ufs_hba *hba)
 	return err;
 }
 
-static void ufs_mtk_udelay(unsigned long us)
-{
-	if (!us)
-		return;
-
-	if (us < 10)
-		udelay(us);
-	else
-		usleep_range(us, us + 10);
-}
-
 static int ufs_mtk_setup_ref_clk(struct ufs_hba *hba, bool on)
 {
 	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
@@ -123,7 +112,7 @@ static int ufs_mtk_setup_ref_clk(struct ufs_hba *hba, bool on)
 
 	if (on) {
 		ufs_mtk_ref_clk_notify(on, res);
-		ufs_mtk_udelay(host->ref_clk_ungating_wait_us);
+		ufshcd_delay_us(host->ref_clk_ungating_wait_us, 10);
 		ufshcd_writel(hba, REFCLK_REQUEST, REG_UFS_REFCLK_CTRL);
 	} else {
 		ufshcd_writel(hba, REFCLK_RELEASE, REG_UFS_REFCLK_CTRL);
@@ -150,7 +139,7 @@ static int ufs_mtk_setup_ref_clk(struct ufs_hba *hba, bool on)
 out:
 	host->ref_clk_enabled = on;
 	if (!on) {
-		ufs_mtk_udelay(host->ref_clk_gating_wait_us);
+		ufshcd_delay_us(host->ref_clk_gating_wait_us, 10);
 		ufs_mtk_ref_clk_notify(on, res);
 	}