Proper detection of _mm_cvtss_si32 for MS compiler

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
diff --git a/celt/float_cast.h b/celt/float_cast.h
index 98b40ab..f218e86 100644
--- a/celt/float_cast.h
+++ b/celt/float_cast.h
@@ -96,7 +96,7 @@
 #include <math.h>
 #define float2int(x) lrint(x)
 
-#elif (defined(_MSC_VER) && _MSC_VER >= 1400) && defined (_M_X64)
+#elif (defined(_MSC_VER) && _MSC_VER >= 1400) && (defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 1))
         #include <xmmintrin.h>
 
         __inline long int float2int(float value)