dmaengine: idxd: remove set but not used variable 'idxd_cdev'

drivers/dma/idxd/cdev.c: In function idxd_cdev_open:
drivers/dma/idxd/cdev.c:77:20: warning:
 variable idxd_cdev set but not used [-Wunused-but-set-variable]

commit 42d279f9 ("dmaengine: idxd: add char driver to
expose submission portal to userland") involed this.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20200210151855.55044-1-yuehaibing@huawei.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/idxd/cdev.c

@@ -74,12 +74,10 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
 	struct idxd_device *idxd;
 	struct idxd_wq *wq;
 	struct device *dev;
-	struct idxd_cdev *idxd_cdev;
 
 	wq = inode_wq(inode);
 	idxd = wq->idxd;
 	dev = &idxd->pdev->dev;
-	idxd_cdev = &wq->idxd_cdev;
 
 	dev_dbg(dev, "%s called\n", __func__);