KVM: x86 emulator: add ->fix_hypercall() callback

Artificial, but needed to remove direct calls to KVM.

Signed-off-by: Avi Kivity <avi@redhat.com>

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

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

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

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