kexec: Enable zstd in kexec decompression paths

The kexec decompression routines support detecting zlib or lzma
compressed images. Lets add the ability to automatically decompress
zstd ones as well. The zstd attempt is made after gzip because its
fairly inexpensive relative lzma, and gzip remains a popular option.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Pingfan Liu <piliu@redhat.com>
Signed-off-by: Simon Horman <horms@kernel.org>
2 files changed