commit 95047b0519c17a28e09df5f38750f5354e3db4c4 upstream.

This refactors compression initialization slightly to better handle
getting potentially called twice (via early pstore_register() calls
and later pstore_init()) and improves the comments and reporting to be
more verbose.
Signed-off-by: NKees Cook <keescook@chromium.org>
Tested-by: NGuenter Roeck <groeck@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>