doc: releases: migration guide: 4.4: add entry for CAN Kconfig changes

Mention the CAN controller driver Kconfig namespace changes in the
migration guide.

Signed-off-by: Henrik Brix Andersen <henrik@brixandersen.dk>

Author: henrikbrixandersen

doc/releases/migration-guide-4.4.rst

@@ -39,6 +39,28 @@ Device Drivers and Devicetree
 
 .. zephyr-keep-sorted-start re(^\w)
 
+Controller Area Network (CAN)
+=============================
+
+* Removed ``CONFIG_CAN_MAX_FILTER``, ``CONFIG_CAN_MAX_STD_ID_FILTER``,
+  ``CONFIG_CAN_MAX_EXT_ID_FILTER``, and ``CONFIG_CAN_MAX_MB``. These are replaced by the following
+  driver-specific Kconfig symbols, some of which have had their default value increased to meet
+  typical software needs:
+
+  * :kconfig:option:`CONFIG_CAN_LOOPBACK_MAX_FILTER` for :dtcompatible:`zephyr,can-loopback`
+  * :kconfig:option:`CONFIG_CAN_MAX32_MAX_FILTER` for :dtcompatible:`adi,max32-can`
+  * :kconfig:option:`CONFIG_CAN_MCP2515_MAX_FILTER` for :dtcompatible:`microchip,mcp2515`
+  * :kconfig:option:`CONFIG_CAN_MCP251XFD_MAX_FILTER` for :dtcompatible:`microchip,mcp251xfd`
+  * :kconfig:option:`CONFIG_CAN_MCUX_FLEXCAN_MAX_FILTER` for :dtcompatible:`nxp,flexcan`
+  * :kconfig:option:`CONFIG_CAN_MCUX_FLEXCAN_MAX_MB` for :dtcompatible:`nxp,flexcan`
+  * :kconfig:option:`CONFIG_CAN_NATIVE_LINUX_MAX_FILTER` for :dtcompatible:`zephyr,native-linux-can`
+  * :kconfig:option:`CONFIG_CAN_SJA1000_MAX_FILTER` for :dtcompatible:`kvaser,pcican` and :dtcompatible:`espressif,esp32-twai`
+  * :kconfig:option:`CONFIG_CAN_STM32_BXCAN_MAX_EXT_ID_FILTER` for :dtcompatible:`st,stm32-bxcan`
+  * :kconfig:option:`CONFIG_CAN_STM32_BXCAN_MAX_STD_ID_FILTER` for :dtcompatible:`st,stm32-bxcan`
+  * :kconfig:option:`CONFIG_CAN_STM32_FDCAN_MAX_EXT_ID_FILTER` for :dtcompatible:`st,stm32-fdcan`
+  * :kconfig:option:`CONFIG_CAN_STM32_FDCAN_MAX_STD_ID_FILTER` for :dtcompatible:`st,stm32-fdcan`
+  * :kconfig:option:`CONFIG_CAN_XMC4XXX_MAX_FILTER` for :dtcompatible:`infineon,xmc4xxx-can-node`
+
 Ethernet
 ========