env: Move env_get_f() to env.h

Move this function over to the new header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

include/common.h

@@ -162,18 +162,6 @@ int	envmatch     (uchar *, int);
  */
 char *env_get(const char *varname);
 
-/**
- * env_get_f() - Look up the value of an environment variable (early)
- *
- * This function is called from env_get() if the environment has not been
- * loaded yet (GD_FLG_ENV_READY flag is 0). Some environment locations will
- * support reading the value (slowly) and some will not.
- *
- * @varname:	Variable to look up
- * @return value of variable, or NULL if not found
- */
-int env_get_f(const char *name, char *buf, unsigned len);
-
 /**
  * env_get_ulong() - Return an environment variable as an integer value
  *