add first boot set hostname

Copy this script and systemd unit file from meta-openpower.

Change-Id: I98aed26efb2be00f1fe3d703f83fd201f18059db
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/firstboot/meson.build b/firstboot/meson.build
index d2d09d7..06a139e 100644
--- a/firstboot/meson.build
+++ b/firstboot/meson.build
@@ -1,4 +1,5 @@
 set_mac = dependency('systemd', required: get_option('first-boot-set-mac'))
+set_hostname = dependency('systemd', required: get_option('first-boot-set-hostname'))
 
 if set_mac.found()
     install_data(
@@ -15,3 +16,19 @@
             set_mac.get_pkgconfig_variable('systemdsystemunitdir'),
     )
 endif
+
+if set_hostname.found()
+    install_data(
+        'first-boot-set-hostname.sh',
+        install_mode: 'rwxr-xr-x',
+        install_dir: get_option('bindir'),
+    )
+
+    configure_file(
+        input: 'first-boot-set-hostname.service',
+        output: 'first-boot-set-hostname.service',
+        copy: true,
+        install_dir:
+            set_hostname.get_pkgconfig_variable('systemdsystemunitdir'),
+    )
+endif