libxc: provide interface for generic resource access

libxc: provide interface for generic resource access

Xen added a new platform_op hypercall for generic MSR access, and this
is the the tool side change to wrapper the hypercall into xc APIs.

For non-preemptible batch resource operations, group them in entries of
xc_resource_op structure. For preemptible ones, use multiple
xc_resource_op structure instead.

Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Release-Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>