It wasn't obvious at all that the backport of commit 0d6968635c
("hvmloader: avoid tests when they would clobber used memory") has
further dependencies on changes all having appeared in the 4.8 dev
cycle. Granted I should have done a build test, yet I routinely do so
only on the hypervisor side ...
Drop all uses of hvm_start_info again.
Signed-off-by: Jan Beulich <jbeulich@suse.com>