add missed options to man page

several options are missed in man page, add it now. They are
--reuseinitrd, --load-preserve-context, --load-jump-back-helper
and --entry=<addr>.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
1 file changed