Documentation/releases: Add W530 mainboard to 4.9 relnotes

Change-Id: I9651b24dd68f9a5e324a4532c3cebac32aacca7e
Signed-off-by: Evgeny Zinoviev <me@ch1p.com>
Reviewed-on: https://review.coreboot.org/c/26885
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

Documentation/releases/coreboot-4.9-relnotes.md

@@ -26,6 +26,10 @@ General changes
 * Rename the POWER8 architecture port to PPC64 to reflect that it isn't limited
   to POWER8
 
+Added mainboards
+----------------
+* Lenovo W530                                          Intel Ivybridge
+
 Toolchain
 ---------