Fix mov syntax

Author: martin-frbg

common_x86_64.h

@@ -129,7 +129,7 @@ static __inline void cpuid(int op, int *eax, int *ebx, int *ecx, int *edx){
   *ecx=cpuinfo[2];
   *edx=cpuinfo[3];
 #else
-        __asm__ __volatile__("mov %%ecx, 0;"
+        __asm__ __volatile__("mov $0, %%ecx;"
 			     "cpuid"
 			     : "=a" (*eax),
 			     "=b" (*ebx),