[patch v2] spi/xilinx: signedness issue checking platform_get_irq()

[Dan Carpenter <dan.carpenter@oracle.com>]

In xilinx_spi_probe() we use xspi->irq to store negative error codes so
it has to be signed.  We weren't going to use the upper bit any way so
this is fine.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2:  The first version introduced an ugly cast.  Sorry for that.

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index fea815c..0f4a093 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -82,7 +82,7 @@ struct xilinx_spi {
 	struct completion done;
 	void __iomem	*regs;	/* virt. address of the control registers */
 
-	u32		irq;
+	int		irq;
 
 	u8 *rx_ptr;		/* pointer in the Tx buffer */
 	const u8 *tx_ptr;	/* pointer in the Rx buffer */