Fix another instance of Packet2l on win32.

Eigen/src/Core/arch/SSE/PacketMath.h

diff --git a/Eigen/src/Core/arch/SSE/PacketMath.h b/Eigen/src/Core/arch/SSE/PacketMath.h
index 64ffdf3..97c8ac8 100644
--- a/Eigen/src/Core/arch/SSE/PacketMath.h
+++ b/Eigen/src/Core/arch/SSE/PacketMath.h
@@ -1641,7 +1641,11 @@
 }
 template <>
 EIGEN_STRONG_INLINE int64_t pfirst<Packet2l>(const Packet2l& a) {
+#if EIGEN_ARCH_x86_64
   int64_t x = _mm_cvtsi128_si64(a);
+#else
+  int64_t x = numext::bit_cast<int64_t>(_mm_cvtsd_f64(_mm_castsi128_pd(a)));
+#endif
   return x;
 }
 template <>