erofs: fix wrong kunmap when using LZMA on HIGHMEM platforms

In the Linux kernel, the following vulnerability has been resolved:

erofs: fix wrong kunmap when using LZMA on HIGHMEM platforms

As the call trace shown, the root cause is kunmap incorrect pages:

BUG: kernel NULL pointer dereference, address: 00000000

CPU: 1 PID: 40 Comm: kworker/u5:0 Not tainted 6.2.0-rc5 #4

Workqueue: erofs_worker z_erofs_decompressqueue_work

EIP: z_erofs_lzma_decompress+0x34b/0x8ac

z_erofs_decompress+0x12/0x14

z_erofs_decompress_queue+0x7e7/0xb1c

z_erofs_decompressqueue_work+0x32/0x60

process_one_work+0x24b/0x4d8

? process_one_work+0x1a4/0x4d8

worker_thread+0x14c/0x3fc

kthread+0xe6/0x10c

? rescuer_thread+0x358/0x358

? kthread_complete_and_exit+0x18/0x18

ret_from_fork+0x1c/0x28

---[ end trace 0000000000000000 ]---

The bug is trivial and should be fixed now. It has no impact on

!HIGHMEM platforms.