KVM: x86: change PT_FIRST_AVAIL_BITS_SHIFT to avoid conflict with EPT Dirty bit

EPT Dirty bit use bit 9 as Intel SDM definition, to avoid conflict, change
PT_FIRST_AVAIL_BITS_SHIFT to 10.
Signed-off-by: NXudong Hao <xudong.hao@intel.com>
Signed-off-by: NXiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/mmu.c

@@ -90,7 +90,7 @@ module_param(dbg, bool, 0644);
 
 #define PTE_PREFETCH_NUM		8
 
-#define PT_FIRST_AVAIL_BITS_SHIFT 9
+#define PT_FIRST_AVAIL_BITS_SHIFT 10
 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
 
 #define PT64_LEVEL_BITS 9