serial: doc: Un-document non-existing uart_write_console()

uart_write_console() never existed, not even when the "new
uart_write_console function" was documented.

Fixes: 67ab7f59 ("[SERIAL] Update serial driver documentation")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/serial/driver

@@ -28,11 +28,6 @@ The serial core provides a few helper functions.  This includes identifing
 the correct port structure (via uart_get_console) and decoding command line
 arguments (uart_parse_options).
 
-There is also a helper function (uart_write_console) which performs a
-character by character write, translating newlines to CRLF sequences.
-Driver writers are recommended to use this function rather than implementing
-their own version.
-
 
 Locking
 -------