enable per-VCPU parameter for RTDS

enable per-VCPU parameter for RTDS

Add XEN_DOMCTL_SCHEDOP_getvcpuinfo and _putvcpuinfo hypercalls
to independently get and set the scheduling parameters of each
vCPU of a domain.

Also fix a bug in XEN_DOMCTL_SCHEDOP_getinfo, where PERIOD and
BUDGET are not divided by MICROSECS(1) before being retruned
to the caller.

Signed-off-by: Chong Li <chong.li@wustl.edu>
Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
Signed-off-by: Sisu Xi <xisisu@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Dario Faggioli <dario.faggioli@citrix.com>