Nokia RX-51: Add automated test for running RX-51 build in qemu

This patch contains test/nokia_rx51_test.sh script which automatically
download and compile all needed tools in local temporary directory to
generate a simple MTD images for booting Maemo kernel image by U-Boot from
RAM, eMMC and OneNAND. MTD images are then run in virtual n900 machine
provided by qemu-linaro project.

This script does not need any special privileges, so it can be run as
non-root nobody user.

It can be used to check that U-Boot for Nokia N900 is not broken and can be
successfully booted in emulator.

Script is registered to .azure-pipelines.yml, .gitlab-ci.yml and
.travis.yml so it would be automatically run on those CI services.

Signed-off-by: Pali Rohár <pali@kernel.org>

.travis.yml

@@ -50,6 +50,8 @@ addons:
     - mtools
     - openssl
     - sbsigntool
+    - fakeroot
+    - mtd-utils
 
 install:
  # Clone uboot-test-hooks
@@ -492,6 +494,11 @@ matrix:
       script:
         - make tools-only_config envtools -j$(nproc)
 
+    - name: "Run tests for Nokia RX-51 (aka N900)"
+      script:
+        - export PATH=~/.buildman-toolchains/gcc-9.2.0-nolibc/arm-linux-gnueabi/bin/:$PATH
+        - test/nokia_rx51_test.sh
+
     # test/py
     - name: "test/py sandbox"
       env: