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>
diff --git a/drivers/spi/bfin_spi.c b/drivers/spi/bfin_spi.c
index 71a31d0..9a6fc78 100644
--- a/drivers/spi/bfin_spi.c
+++ b/drivers/spi/bfin_spi.c
@@ -9,6 +9,7 @@
 /*#define DEBUG*/
 
 #include <common.h>
+#include <console.h>
 #include <malloc.h>
 #include <spi.h>