EM installer updates

scripts/install-obsw-yocto.sh

@@ -2,13 +2,10 @@
 # This is a helper script to install the compiles EIVE OBSW files
 # into the yocto repository to re-generate the mission root filesystem
 build_dir=cmake-build-release-q7s
-em_install="0"
-if [ ! -z ${1} ]; then
-  if [[ "${1}" == "em" ]]; then
-    echo "-I- Installing EM binaries"
-    em_install="1"
-    build_dir=cmake-build-release-q7s-em
-  fi
+if [ ! -z ${1} && "${1}" == "em" ] || [[ ${EIVE_Q7S_EM} == "1" ]]; then
+  echo "-I- Installing EM binaries"
+  em_install="1"
+  build_dir=cmake-build-release-q7s-em
 fi
 
 init_dir=$(pwd)