The RMM keeps track of the timer while the realm REC is running, but on
exit to the normal world KVM is responsible for handling the timers.
The RMM doesn't provide a mechanism to set the counter offset, so don't
expose KVM_CAP_COUNTER_OFFSET for a realm VM.
A later patch adds the support for propagating the timer values from the
exit data structure and calling kvm_realm_timers_update().
Signed-off-by: Steven Price <steven.price@xxxxxxx>