From: Stefano Stabellini
Remove dummy arm implementation of wallclock_time.
Use shared_info() in common code rather than x86-ism to access it, when
possible.
Define the static variable wc_sec, and the local variale sec in
update_domain_wallclock_time, as uint64_t instead of unsigned long, to
avo
From: Stefano Stabellini
Call update_domain_wallclock_time at domain initialization, specifically
in arch_set_info_guest for vcpu0, like we do on x86.
Set time_offset_seconds to the number of seconds between phisical boot
and domain initialization: it is going to be used to get/set the
wallclock
