x86/intmath: add missing early clobber to output operands

Signed-off-by: James Almer <jamrial@gmail.com>

libavutil/x86/intmath.h

@@ -109,7 +109,7 @@ static av_always_inline av_const double av_clipd_sse2(double a, double amin, dou
 #endif
     __asm__ ("minsd %2, %0 \n\t"
              "maxsd %1, %0 \n\t"
-             : "+x"(a) : "xm"(amin), "xm"(amax));
+             : "+&x"(a) : "xm"(amin), "xm"(amax));
     return a;
 }
 
@@ -125,7 +125,7 @@ static av_always_inline av_const float av_clipf_sse(float a, float amin, float a
 #endif
     __asm__ ("minss %2, %0 \n\t"
              "maxss %1, %0 \n\t"
-             : "+x"(a) : "xm"(amin), "xm"(amax));
+             : "+&x"(a) : "xm"(amin), "xm"(amax));
     return a;
 }