WORKSPACE: bump Linux to 5.15.2

This involves ripping out fsinfo because there now is quotactl_fd which
handles what we originally used fsinfo for. I also enabled a few new
interesting kernel features in the config like the Landlock LSM and
KFENCE.

Change-Id: Ic0a113893a437b2c8068d06984fdc386f34e6adb
Reviewed-on: https://review.monogon.dev/c/monogon/+/444
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/WORKSPACE b/WORKSPACE
index f81e37c..8e83327 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -121,7 +121,7 @@
 
 linux_external(
     name = "linux",
-    version = "5.10.4",
+    version = "5.15.2",
 )
 
 load("//third_party/edk2:external.bzl", "edk2_external")