KVM: ia64: Add optimization for some virtulization faults

optvfault.S Add optimization for some performance-critical
virtualization faults.
Signed-off-by: Anthony Xu <anthony.xu@intel.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>