spi: atmel-quadspi: remove unnecessary cast

The cast is done implicitly.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/atmel-quadspi.c

@@ -389,7 +389,7 @@ static int atmel_qspi_init(struct atmel_qspi *aq)
 
 static irqreturn_t atmel_qspi_interrupt(int irq, void *dev_id)
 {
-	struct atmel_qspi *aq = (struct atmel_qspi *)dev_id;
+	struct atmel_qspi *aq = dev_id;
 	u32 status, mask, pending;
 
 	status = readl_relaxed(aq->regs + QSPI_SR);