KVM: mark the function 'inline' defined in .h file

fix:
arch/x86/include/asm/kvm_para.h:185: warning: ‘kvm_read_and_reset_pf_reason’ defined but not used
CC [M] arch/x86/kvm/x86.o
arch/x86/include/asm/kvm_para.h:185: warning: ‘kvm_read_and_reset_pf_reason’ defined but not used
CC [M] arch/x86/kvm/mmu.o
arch/x86/include/asm/kvm_para.h:185: warning: ‘kvm_read_and_reset_pf_reason’ defined but not used
CC [M] arch/x86/kvm/emulate.o

---
 arch/x86/include/asm/kvm_para.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index d3a1a48..a427bf7 100644
@@ -182,7 +182,7 @@ u32 kvm_read_and_reset_pf_reason(void);
 #define kvm_guest_init() do { } while (0)
 #define kvm_async_pf_task_wait(T) do {} while(0)
 #define kvm_async_pf_task_wake(T) do {} while(0)
-static u32 kvm_read_and_reset_pf_reason(void)
+static inline u32 kvm_read_and_reset_pf_reason(void)
 {
 	return 0;
 }

1.7.0.4