LU-14865 utils: llog_reader.c printf type mismatch

LU-14865 utils: llog_reader.c printf type mismatch

Add (unsigned long long) cast to results of
__le64_to_cpu so that it matches the formatting (%llu)
of the enclosing printf call.

Build log message:
"llog_reader.c:887:9: error: format '%llu' expects
argument of type 'long long unsigned int', but
argument 3 has type '__u64' [-Werror=format=]"

Test-Parameters: trivial
Fixes: 9962d6f84db5 LU-14617 utils: llog_reader updatelog support
Signed-off-by: Gian-Carlo DeFazio <defazio1@llnl.gov>
Change-Id: I9549e0a0bd21727dfcc42992b693bc39a779e1a1
Reviewed-on: https://review.whamcloud.com/44346
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>