KVM: Portability: Split mmu-related static inline functions to mmu.h

Since these functions need to know the details of kvm or kvm_vcpu structure,
it can't be put in x86.h.  Create mmu.h to hold them.

Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index da1dedb..1dc0e8c 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -20,6 +20,7 @@
 #include "vmx.h"
 #include "kvm.h"
 #include "x86.h"
+#include "mmu.h"
 
 #include <linux/types.h>
 #include <linux/string.h>