kconfigcheck: add BTRFS_FS_POSIX_ACL

This is required for running journalctl without root, see:
!6145 (comment 470989)

kconfigcheck.toml

@@ -276,6 +276,7 @@ NF_CONNTRACK_MARK = true
 # filesystems
 ["category:filesystems".">=0.0.0"."all"]
 BTRFS_FS = true
+BTRFS_FS_POSIX_ACL = true
 EXFAT_FS = true
 EXT4_FS = true
 F2FS_FS = true