test/py: Allow using buildman to build U-Boot

It is a pain to have to set the CROSS_COMPILE environment variable when
using test.py's --build option. It is possible to get this using the -A
option from buildman. But it seems better to just use buildman to do the
build when it is available.

However using buildman adds a new dependency to the test system which we
want to avoid. So leave the default as is and add a flag to make it use
buildman.

Note that most of these changes relate to test.py and the parts of the
travis/gitlab/azure scripts which relate to running test and building a
suitable U-Boot to run the tests on.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/test/py/README.md b/test/py/README.md
index 3cbe01b..2e50252 100644
--- a/test/py/README.md
+++ b/test/py/README.md
@@ -138,6 +138,9 @@
   before running the tests. If using this option, make sure that any
   environment variables required by the build process are already set, such as
   `$CROSS_COMPILE`.
+- `--buildman` indicates that `--build` should use buildman to build U-Boot.
+  There is no need to set $CROSS_COMPILE` in this case since buildman handles
+  it.
 - `--build-dir` sets the directory containing the compiled U-Boot binaries.
   If omitted, this is `${source_dir}/build-${board_type}`.
 - `--result-dir` sets the directory to write results, such as log files,
@@ -333,7 +336,7 @@
 
 If you want the test script to compile U-Boot for you too, then you likely
 need to set `$CROSS_COMPILE` to allow this, and invoke the test script as
-follow:
+follows:
 
 ```bash
 CROSS_COMPILE=arm-none-eabi- \
@@ -342,6 +345,14 @@
     ./test/py/test.py --bd seaboard --build
 ```
 
+or, using buildman to handle it:
+
+```bash
+    PATH=$HOME/ubtest/bin:$PATH \
+    PYTHONPATH=${HOME}/ubtest/py/${HOSTNAME}:${PYTHONPATH} \
+    ./test/py/test.py --bd seaboard --build --buildman
+```
+
 ## Writing tests
 
 Please refer to the pytest documentation for details of writing pytest tests.