Emit error when board.h or config_chip.h is included before config.h

If board.h or config_chip.h is included before config.h, CONFIG_* flags
may be incorrect. For example, if config.h says:

    ...
  #define CONFIG_DEFINED_FLAG
    ...
  #include "board.h"
    ...

And board.h says:

  #ifndef __BOARD_H
  #define __BOARD_H
    ...
  #undef CONFIG_DEFINED_FLAG
    ...
  #endif

Then this code:

  #include "board.h"
  #include "config.h"

would results in CONFIG_DEFINED_FLAG being defined, instead of undefined
as stated in board.h.

Avoid this by emitting error when board.h or config_chip.h is included
before config.h.

BUG=None
TEST=make buildall
BRANCH=None

Change-Id: Ic4a8b68e8ab1ef2a4cf9e926ab9008d2b106b943
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/203265
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

board/fruitpie/usb_pd_policy.c

@@ -3,7 +3,6 @@
  * found in the LICENSE file.
  */
 
-#include "board.h"
 #include "common.h"
 #include "console.h"
 #include "gpio.h"

board/keyborg/board.c

@@ -4,7 +4,6 @@
  */
 /* Keyborg board-specific configuration */
 
-#include "board.h"
 #include "common.h"
 #include "debug.h"
 #include "master_slave.h"

board/keyborg/debug.c

@@ -4,7 +4,6 @@
  */
 /* GPIO UART debug printf */
 
-#include "board.h"
 #include "common.h"
 #include "printf.h"
 #include "registers.h"

board/keyborg/master_slave.c

@@ -4,7 +4,7 @@
  */
 /* Master/slave identification */
 
-#include "board.h"
+#include "config.h"
 #include "debug.h"
 #include "master_slave.h"
 #include "registers.h"

board/keyborg/spi_comm.c

@@ -4,7 +4,6 @@
  */
 /* Stantum board-specific SPI module */
 
-#include "board.h"
 #include "common.h"
 #include "debug.h"
 #include "dma.h"

board/samus_pd/usb_pd_policy.c

@@ -3,7 +3,6 @@
  * found in the LICENSE file.
  */
 
-#include "board.h"
 #include "common.h"
 #include "console.h"
 #include "gpio.h"

include/config.h

@@ -954,6 +954,13 @@
  * Board is included after chip, so that chip defaults can be overridden on a
  * per-board basis as needed.
  */
+#ifdef __CROS_EC_CONFIG_CHIP_H
+#error Include config.h instead of config_chip.h!
+#endif
+#ifdef __BOARD_H
+#error Include config.h instead of board.h!
+#endif
+
 #include "config_chip.h"
 #include "board.h"