imx-drm: ipu-dmfc: Remove unneeded 'dmfc' check

Fix the following static checker warning:

drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c:164 ipu_dmfc_setup_channel() warn: variable dereferenced before check 'dmfc' (see line 157)

As 'dmfc' could never be null, there is no need to do such check.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/imx-drm/ipu-v3/ipu-dmfc.c

@@ -161,9 +161,6 @@ static int ipu_dmfc_setup_channel(struct dmfc_channel *dmfc, int slots,
 			"dmfc: using %d slots starting from segment %d for IPU channel %d\n",
 			slots, segment, dmfc->data->ipu_channel);
 
-	if (!dmfc)
-		return -EINVAL;
-
 	switch (slots) {
 	case 1:
 		field = DMFC_FIFO_SIZE_64;