Docs: Update boards supported on branches document

- Update the notes for the 4.19 release.
- Add the intel/icelake_rvp board as being supported on the 4.19 branch.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: I5c283f64efc465d8f70fc19d570c5b7547474e80
Reviewed-on: https://review.coreboot.org/c/coreboot/+/72481
Reviewed-by: Jason Glenesk <jason.glenesk@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>

Documentation/releases/boards_supported_on_branches.md

@@ -12,9 +12,9 @@ desired.
 
 Currently, [jenkins](https://qa.coreboot.org), our continuous
 integration system is configured to build the 4.11, 4.12, 4.14, 4.15,
-4.16, and 4.18 branches.  Builders for other branches can be created on
+4.16, 4.18, and 4.19 branches.  Builders for other branches can be
-request.  Likewise, some releases are only marked with tags, and
+added upon request.  Likewise, some releases are only marked with tags,
-branches would need to be created to push new code to.  These branches
+and branches would need to be created to push new code.  These branches
 can also be created on request.
 
 Patches can be backported from the master branch to any of these other
@@ -23,6 +23,17 @@ critical security fixes, but other patches will need to handled by
 anyone using that release.
 
 
+## [4.19 Release](coreboot-4.19-relnotes.md)
+Branch created, builder configured
+
+```eval_rst
++-------------------------------+------------------------+------------+-----------+
+| Vendor/Board                  | Processor              | Date added | Brd type  |
++===============================+========================+============+===========+
+| intel/icelake_rvp             | INTEL_ICELAKE          | 2018-10-26 | eval      |
++-------------------------------+------------------------+------------+-----------+
+```
+
 ## [4.18 Release](coreboot-4.18-relnotes.md)
 Branch created, builder configured