Ensure we only use en_us locale

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/conf/distro/openbmc-phosphor.conf b/conf/distro/openbmc-phosphor.conf
index 69ec16f..3625cea 100644
--- a/conf/distro/openbmc-phosphor.conf
+++ b/conf/distro/openbmc-phosphor.conf
@@ -6,6 +6,7 @@
 TARGET_VENDOR="-openbmc"
 
 IMAGE_FSTYPES += "cpio.gz"
+IMAGE_LINGUAS = "en-us"
 
 VIRTUAL-RUNTIME_keymaps = ""