systemd: fix locale

Systemd picks the C.UTF-8 locale as supported based on a check of the
build env. That's bogous for cross-builds, there's nothing like that in
glibc so far.

Bug: https://github.com/systemd/systemd/issues/11259
Change-Id: Ie0deb19893ced8deff57036a9b722bd36c1bfc20
diff --git a/configs/czechlight_clearfog_defconfig b/configs/czechlight_clearfog_defconfig
index 62cba2d..04d62a2 100644
--- a/configs/czechlight_clearfog_defconfig
+++ b/configs/czechlight_clearfog_defconfig
@@ -19,6 +19,8 @@
 BR2_TARGET_GENERIC_GETTY_PORT="ttyS0"
 BR2_TARGET_GENERIC_GETTY_BAUDRATE_115200=y
 # BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW is not set
+BR2_ENABLE_LOCALE_WHITELIST="C en_US C.UTF-8 en_US.UTF-8"
+BR2_GENERATE_LOCALE="en_US.UTF-8"
 BR2_ROOTFS_USERS_TABLES="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/common/users"
 BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/common/overlay/ $(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/clearfog/overlay/"
 BR2_ROOTFS_POST_BUILD_SCRIPT="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/clearfog/post_build.sh"
diff --git a/submodules/buildroot b/submodules/buildroot
index 4aaa013..8dcb383 160000
--- a/submodules/buildroot
+++ b/submodules/buildroot
@@ -1 +1 @@
-Subproject commit 4aaa013f87e968c14e9cde8d24199c6015432237
+Subproject commit 8dcb38396668c9c64cc630cf78c928058867f85b