Update kernel to 5.5.2

Between 5.4 and 5.5, apparently in commit 0e4a459f56c32d3e ("tracing:
Remove unnecessary DEBUG_FS dependency"), CONFIG_DEBUG_FS is no longer
auto-enabled. We're using that interface for obtaining an old-school
GPIO number because, well, that's what the LED GPIO trigger expects.

It would be nice to fix this upstream so that the LED GPIO trigger
accepts, say, a (chipname, gpio number) pair, but ENOTIME.

Change-Id: Ie4e3b37729389f03d7a294d0bc3cecc589ae5ed0
diff --git a/configs/czechlight_clearfog_defconfig b/configs/czechlight_clearfog_defconfig
index 9c24c20..083aad3 100644
--- a/configs/czechlight_clearfog_defconfig
+++ b/configs/czechlight_clearfog_defconfig
@@ -25,7 +25,7 @@
 BR2_ROOTFS_POST_SCRIPT_ARGS="-c $(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/clearfog/genimage.cfg"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.4.1"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.5.2"
 BR2_LINUX_KERNEL_PATCH="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/clearfog/patches/linux.patch"
 BR2_LINUX_KERNEL_DEFCONFIG="mvebu_v7"
 BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/clearfog/linux.fragment $(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/common/linux.fragment"