erofs: fix memory leak of LZMA global compressed deduplication

erofs: fix memory leak of LZMA global compressed deduplication

When stressing microLZMA EROFS images with the new global compressed
deduplication feature enabled (`-Ededupe`), I found some short-lived
temporary pages weren't properly released, which could slowly cause
unexpected OOMs hours later.

Let's fix it now (LZ4 and DEFLATE don't have this issue.)

Fixes: 5c2a64252c5d ("erofs: introduce partial-referenced pclusters")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230907050542.97152-1-hsiangkao@linux.alibaba.com