spi: cf_qspi: Fixup to_cf_qspi_slave macro

The third parameter of container_of is the name of the member within the struct.
Current code only works if the parameter passed to to_cf_qspi_slave named slave.
Fix it.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
diff --git a/drivers/spi/cf_qspi.c b/drivers/spi/cf_qspi.c
index 6b85633..834c5bd 100644
--- a/drivers/spi/cf_qspi.c
+++ b/drivers/spi/cf_qspi.c
@@ -20,7 +20,7 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 #define clamp(x, low, high) (min(max(low, x), high))
-#define to_cf_qspi_slave(s) container_of(s, struct cf_qspi_slave, s)
+#define to_cf_qspi_slave(s) container_of(s, struct cf_qspi_slave, slave)
 
 struct cf_qspi_slave {
 	struct spi_slave slave;	/* Specific bus:cs ID for each device */