Jenkinsfile: move the build type to the front

We need to parse the build type for librem5-devkit-tools. This will
also break librem5-devkit-flash-image so that people don't end up
with radnom images until it gets fixed.
Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>

Jenkinsfile

@@ -5,7 +5,7 @@ node {
    build_on_x86 = [ 'imx6', 'qemu-x86_64' ]
    qcow2_builds = [ 'qemu-x86_64' ]
    separate_boot_image = []
-   currentBuild.description = "${params.board} ${params.dist} ${build_type} image"
+   currentBuild.description = "${build_type} ${params.board} ${params.dist} image"
 
    parameters {
         string(name: 'board', defaultValue: "imx6", description: 'What board type to build for?')