sys/linux/init_alg.go: add new algorithms
sys/linux/init_alg.go: add new algorithms

- Add essiv (new in v5.4)
- Add xxhash64 (new in v5.3)

xairy/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller