Move console definitions into a new console.h file

The console includes a global variable and several functions that are only
used by a small subset of U-Boot files. Before adding more functions, move
the definitions into their own header file.

Signed-off-by: Simon Glass <sjg@chromium.org>

board/xes/xpedite1000/xpedite1000.c

@@ -5,6 +5,7 @@
  */
 
 #include <common.h>
+#include <console.h>
 #include <asm/processor.h>
 #include <spd_sdram.h>
 #include <i2c.h>