Update to v5.15 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-5.15

Test: Builds, and ran bionic unit tests on flame.
Change-Id: I86901ea6d89fb0f7384b90a47bef35d194083c24
diff --git a/libc/kernel/uapi/linux/btrfs.h b/libc/kernel/uapi/linux/btrfs.h
index c0a586c..a40e24d 100644
--- a/libc/kernel/uapi/linux/btrfs.h
+++ b/libc/kernel/uapi/linux/btrfs.h
@@ -175,6 +175,7 @@
 };
 #define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE (1ULL << 0)
 #define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE_VALID (1ULL << 1)
+#define BTRFS_FEATURE_COMPAT_RO_VERITY (1ULL << 2)
 #define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF (1ULL << 0)
 #define BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL (1ULL << 1)
 #define BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS (1ULL << 2)