net: ieee802154: fix potential null pointer dereference

Null check at line 918: if (!spi) {, implies spi might be NULL.
Function spi_get_drvdata() dereference pointer spi.
Move pointer priv assignment after the null check.

Addresses-Coverity-ID: 1408888
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/ca8210.c

@@ -912,7 +912,7 @@ static int ca8210_spi_transfer(
 )
 {
 	int i, status = 0;
-	struct ca8210_priv *priv = spi_get_drvdata(spi);
+	struct ca8210_priv *priv;
 	struct cas_control *cas_ctl;
 
 	if (!spi) {
@@ -923,6 +923,7 @@ static int ca8210_spi_transfer(
 		return -ENODEV;
 	}
 
+	priv = spi_get_drvdata(spi);
 	reinit_completion(&priv->spi_transfer_complete);
 
 	dev_dbg(&spi->dev, "ca8210_spi_transfer called\n");