stdio: Pass device pointer to stdio methods

At present stdio device functions do not get any clue as to which stdio
device is being acted on. Some implementations go to great lengths to work
around this, such as defining a whole separate set of functions for each
possible device.

For driver model we need to associate a stdio_dev with a device. It doesn't
seem possible to continue with this work-around approach.

Instead, add a stdio_dev pointer to each of the stdio member functions.

Note: The serial drivers have the same problem, but it is not strictly
necessary to fix that to get driver model running. Also, if we convert
serial over to driver model the problem will go away.

Code size increases by 244 bytes for Thumb2 and 428 for PowerPC.

22: stdio: Pass device pointer to stdio methods
       arm: (for 2/2 boards)  all +244.0  bss -4.0  text +248.0
   powerpc: (for 1/1 boards)  all +428.0  text +428.0

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/include/configs/nokia_rx51.h b/include/configs/nokia_rx51.h
index e0c0fac..53cb390 100644
--- a/include/configs/nokia_rx51.h
+++ b/include/configs/nokia_rx51.h
@@ -263,9 +263,10 @@
 #define VIDEO_TSTC_FCT			rx51_kp_tstc
 #define VIDEO_GETC_FCT			rx51_kp_getc
 #ifndef __ASSEMBLY__
+struct stdio_dev;
 int rx51_kp_init(void);
-int rx51_kp_tstc(void);
-int rx51_kp_getc(void);
+int rx51_kp_tstc(struct stdio_dev *sdev);
+int rx51_kp_getc(struct stdio_dev *sdev);
 #endif
 
 #ifndef MTDPARTS_DEFAULT