pstore: Fix typo in compression option name

Both pstore_compress() and decompress_record() use a mistyped config
option name ("PSTORE_COMPRESSION" instead of "PSTORE_COMPRESS"). As
a result compression and decompression of pstore records was always
disabled.

Use the correct config option name.

Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Fixes: fd49e032

 ("pstore: Fix linking when crypto API disabled")
Acked-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210218111547.johvp5klpv3xrpnn@dwarf.suse.cz