Doc/releases: Mention that Asus H61 boards got squashed

Not physically squashed, the coreboot code got turned into a variant
setup with override devicetrees to drop redundant boilerplate.

Change-Id: I7ae5530d2603d6d108ef3829004de7e1cad130f9
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/54690
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Christian Walter <christian.walter@9elements.com>
diff --git a/Documentation/releases/coreboot-4.15-relnotes.md b/Documentation/releases/coreboot-4.15-relnotes.md
index 6244cf6..0e2ad7e 100644
--- a/Documentation/releases/coreboot-4.15-relnotes.md
+++ b/Documentation/releases/coreboot-4.15-relnotes.md
@@ -13,4 +13,10 @@
 Significant changes
 -------------------
 
+### Merged family of Asus mainboards using H61 chipset
+
+By using newer coreboot features like board variants and override devicetrees,
+lots of code can now be shared. This should ease maintenance and also make it
+easier for newcomers to add support for even more mainboards.
+
 ### Add significant changes here