github/workflows: Extend CI to compile open boot firmware for RB3Gen2

At this point due to QTI signature requirement, the LAVA boot test for RB3Gen2
can't be enabled. However, lets add the CI build test with open boot firmware.

Signed-off-by: Sumit Garg <[email protected]>

Author: b49020

.github/workflows/build-yocto.yml

@@ -144,6 +144,14 @@ jobs:
                 type: additional
                 dirname: "+linux-yocto-lts"
                 yamlfile: ":ci/linux-yocto-lts.yml"
+          - machine: qcs6490-rb3gen2-core-kit
+            distro:
+                name: qcom-distro
+                yamlfile: ':ci/qcom-distro.yml'
+            firmware:
+                type: additional
+                dirname: "+open-boot-firmware"
+                yamlfile: ":ci/open-boot-firmware.yml"
         exclude:
           # Incompatible builds
           - machine: qcom-armv7a