kvm: x86: Add kvm_x86_ops hook that enables XSAVES for guest

Expose the XSAVES feature to the guest if the kvm_x86_ops say it is
available.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --cc arch/x86/include/asm/kvm_host.h
Simple merge

diff --cc arch/x86/include/asm/vmx.h
Simple merge

diff --cc arch/x86/kvm/cpuid.c
Simple merge

diff --cc arch/x86/kvm/svm.c
Simple merge

diff --cc arch/x86/kvm/vmx.c
Simple merge