console: Add a function to read a line of the output / eof

When recording the console output for testing it is useful to be able to
read the output a line at a time to check that the output is correct. Also
we need to check that we get to the end of the output.

Add a console function to return the next line and another to see how must
data is left.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/console.h b/include/console.h
index e935c601..74afe22 100644
--- a/include/console.h
+++ b/include/console.h
@@ -42,6 +42,25 @@
 void console_record_reset_enable(void);
 
 /**
+ * console_record_readline() - Read a line from the console output
+ *
+ * This reads the next available line from the console output previously
+ * recorded.
+ *
+ * @str: Place to put string
+ * @maxlen: Maximum length of @str including nul terminator
+ * @return length of string returned
+ */
+int console_record_readline(char *str, int maxlen);
+
+/**
+ * console_record_avail() - Get the number of available bytes in console output
+ *
+ * @return available bytes (0 if empty)
+ */
+int console_record_avail(void);
+
+/**
  * console_announce_r() - print a U-Boot console on non-serial consoles
  *
  * When U-Boot starts up with a display it generally does not announce itself