doc: release/4.0: add bits about serial

This adds some bits about serial/UART in the migration
and release notes for 4.0.

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

doc/releases/migration-guide-4.0.rst

@@ -297,6 +297,8 @@ Serial
    can accept data bytes, instead of ``ret == 1``. The function now returns a lower bound on the
    number of bytes that can be provided to :c:func:`uart_fifo_fill` without truncation.
 
+ * LiteX: ``CONFIG_UART_LITEUART`` has been renamed to :kconfig:option:`CONFIG_UART_LITEX`.
+
 Regulator
 =========
 

doc/releases/release-notes-4.0.rst

@@ -449,6 +449,9 @@ Drivers and Sensors
   * LiteX: Renamed the ``compatible`` from ``litex,uart0`` to :dtcompatible:`litex,uart`.
   * Nordic: Removed ``CONFIG_UART_n_GPIO_MANAGEMENT`` Kconfig options (where n is an instance
     index) which had no use after pinctrl driver was introduced.
+  * NS16550: Added support for Synopsys Designware 8250 UART.
+  * Renesas: Added support for SCI UART.
+  * Sensry: Added UART support for Ganymed SY1XX.
 
 * SPI