scsi: ufs: ufs-mediatek: Fix error checking in ufs_mtk_init_va09_pwr_ctrl()

The function regulator_get() returns an error pointer. Use IS_ERR() to
validate the return value.

Link: https://lore.kernel.org/r/20211222070930.9449-1-linmq006@gmail.com
Fixes: cf137b3ea4 ("scsi: ufs-mediatek: Support VA09 regulator operations")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-mediatek.c

@@ -557,7 +557,7 @@ static void ufs_mtk_init_va09_pwr_ctrl(struct ufs_hba *hba)
 	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 
 	host->reg_va09 = regulator_get(hba->dev, "va09");
-	if (!host->reg_va09)
+	if (IS_ERR(host->reg_va09))
 		dev_info(hba->dev, "failed to get va09");
 	else
 		host->caps |= UFS_MTK_CAP_VA09_PWR_CTRL;