Bundle a newer zstd (currently 1.5.2)

[Yury-MonZon]

The bundled zstd is 1.5.2 (include/linux/zstd_lib.h), which dates to 2022 and is several releases behind upstream (1.5.6+). Worth bumping, since later releases carry decode robustness and correctness fixes.

• U-Boot @ b02abe709e76
• include/linux/zstd_lib.h: ZSTD_VERSION_MAJOR/MINOR/RELEASE = 1/5/2

Related: btrfs zstd decompression bug in #35.

[munzzyy]

Took a run at this. Mirrored Linux 1.5.7 over the 1.5.2 we carry and kept the adaptations from the 1.5.2 import.

Two new ones were needed. The 1.5.7 mem.h includes linux/unaligned.h. That is a Linux rename of asm/unaligned.h and U-Boot still has the asm path. Duplicate newlines also need collapsing after 2f8c004.

Verified on sandbox. ut lib passes 133 tests with 0 failures. Both zstd cases included. The aarch64 cross-build is clean. Size delta is text +2920 bytes under ZSTD_LIB_MINIFY.

Belongs upstream rather than as a fork carry. Want me to send it to the list?

torvalds/linux@65d1f5507ed2

[munzzyy]

Sent it to the list: https://patchwork.ozlabs.org/project/uboot/patch/69502f5a39ab3f07b7872cc6dcbf7e86f7e7d42f.1786670589.git.Munzzyy1@proton.me/

Rebuilt and re-measured before it went out. Sandbox ut lib is 133 tests with 0 failures, both zstd cases included, and turris_mox cross-builds clean. Size under CONFIG_ZSTD_LIB_MINIFY=y is text +2888 bytes on sandbox and +1920 on turris_mox, data and bss unchanged.

Tree is at v2026.10-rc2, so I expect it sits until the next merge window.