doc: releases: update disk release notes for 3.2
doc: releases: update disk release notes for 3.2

Update release notes with changes to disk subsystem since 3.1 release.

Signed-off-by: Daniel DeGrasse <002dd1d4ac44ebb71088aae93501e62b784ed821@nxp.com>

galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr