include/linux/lz4.h: add some missing macros

include/linux/lz4.h: add some missing macros

Currently, LZ4_DISTANCE_MAX and LZ4_DECOMPRESS_INPLACE_MARGIN are
defined in the erofs subsystem for LZ4 in-place decompression, which is
somewhat unsuitable since they should belong to the LZ4 itself and
may change with future LZ4 codebase updates.

Move them to include/linux/lz4.h to match the upstream LZ4 library [1].
No logic changes.

[1] https://github.com/lz4/lz4/blob/v1.10.0/lib/lz4.h#L670

Link: https://lkml.kernel.org/r/20250114130454.1191150-1-hsiangkao@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Yann Collet <yann.collet.73@gmail.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Yue Hu <zbestahu@gmail.com>
Cc; Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>