scsi: ufs-mediatek: Enable WriteBooster capability

Enable WriteBooster capability on MediaTek UFS platforms.

Link: https://lore.kernel.org/r/20200508080115.24233-8-stanley.chu@mediatek.comReviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
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

@@ -269,6 +269,9 @@ static int ufs_mtk_init(struct ufs_hba *hba)
 	/* Enable clock-gating */
 	hba->caps |= UFSHCD_CAP_CLK_GATING;
 
+	/* Enable WriteBooster */
+	hba->caps |= UFSHCD_CAP_WB_EN;
+
 	/*
 	 * ufshcd_vops_init() is invoked after
 	 * ufshcd_setup_clock(true) in ufshcd_hba_init() thus