release-notes: Add new Intel and NXP xtensa ADSP tools.

Add details of the new xtensa targets from Intel and NXP.
GDB 8.3.1 update for xtensa.

Signed-off-by: Liam Girdwood <[email protected]>

Author: lrgirdwo

release-notes.md

@@ -13,3 +13,6 @@
   On newer fedora systems this can show up and be fixed by:
 
   `sudo dnf install python36`
+- Added support for Intel BDW and BDW Audio DSP xtensa toolchains.
+- Added support for NXP IMX8 and IMX8M Audio DSP xtensa toolchains.
+- Updated xtensa targets to GDB 8.3.1