spi: pl022: don't use uninitialized variable

The num-cs property is a required property according to the binding
documentation.  However, if it is not present, the driver currently
simply uses random junk from the stack for the num-cs since the variable
whose pointer is passed to of_property_read_u32() is not initialized.

Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index f7f7ba1..2f76e02 100644
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -2074,7 +2074,7 @@
 {
 	struct device_node *np = dev->of_node;
 	struct pl022_ssp_controller *pd;
-	u32 tmp;
+	u32 tmp = 0;
 
 	if (!np) {
 		dev_err(dev, "no dt node defined\n");