setup: allow simple execution for machine list

Move the if-block that detects if we were running as a `source`
or direct invocation, so that the machine list can be obtained
more regularly.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ica3dde8b3efba0affff3cf884f4059bb141dd802
diff --git a/setup b/setup
index a7a16a1..823cc1b 100755
--- a/setup
+++ b/setup
@@ -15,10 +15,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-if [ -z "$ZSH_NAME" ] && [ "$(basename -- "$0")" = "setup" ]; then
-    echo The script must be sourced, not executed
-    exit 1
-fi
 
 # Check if 'column' command is present
 COLUMN_CMD=$(which column || true)
@@ -97,11 +93,16 @@
     echo Target machine must be specified. Use one of:
     echo
     machine | sort | sed "s/qemu[^[:space:]]*//" | "${COLUMN[@]}"
-else
-    bld_dir=$2
-    if [ -z "$2" ]; then
-        bld_dir="build/$1"
-    fi
-    machine "$1" "$bld_dir"
+    exit
 fi
 
+if [ -z "$ZSH_NAME" ] && [ "$(basename -- "$0")" = "setup" ]; then
+    echo The script must be sourced, not executed
+    exit 1
+fi
+
+bld_dir=$2
+if [ -z "$2" ]; then
+    bld_dir="build/$1"
+fi
+machine "$1" "$bld_dir"