HV: Fix the incorrect operand-constraints for inline assembly

The RFLAGS will be touched in some inline assembly.(exec_vmxon/
RFLAGS_RESTORE). The "cc" constraint should be added. Otherwise
it won't be handled under -O2 option.
And "%%XXX" register should also be added into constraints.
Otherwise it will be optimized incorrectly.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Zheng Gen <gen.zheng@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

hypervisor/include/arch/x86/cpu.h

@@ -379,8 +379,9 @@ void load_cpu_state_data(void);
 /* Macro to restore rflags register */
 #define CPU_RFLAGS_RESTORE(rflags)                      \
 {                                                       \
-	asm volatile (" push %0" : : "r" (rflags));     \
-	asm volatile (" popf");                         \
+	asm volatile (" push %0\n\t"			\
+			"popf	\n\t": : "r" (rflags)	\
+			:"cc");				\
 }
 
 /* This macro locks out interrupts and saves the current architecture status