doc: release notes: added opamp release notes

Added opamp support to release notes for release 4.3

Signed-off-by: Zhaoxiang Jin <Zhaoxiang.Jin_1@nxp.com>

Author: ZhaoxiangJin

doc/releases/release-notes-4.3.rst

@@ -106,6 +106,12 @@ New APIs and options
     * :c:macro:`LOG_HEXDUMP_INF_RATELIMIT_RATE` - Rate-limited info hexdump macro (explicit rate)
     * :c:macro:`LOG_HEXDUMP_DBG_RATELIMIT_RATE` - Rate-limited debug hexdump macro (explicit rate)
 
+* Opamp
+
+  * Introduced opamp device driver subsystem selected with :kconfig:option:`CONFIG_OPAMP`
+  * Added support for NXP OPAMP (:dtcompatible:`nordic,opamp`)
+  * Added support for NXP OPAMP_FAST (:dtcompatible:`nxp,opamp_fast`)
+
 * Power management
 
    * :c:func:`pm_device_driver_deinit`