Turn off vectorize version of rsqrt - doesn't match generic version

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

diff --git a/Eigen/src/Core/arch/AltiVec/PacketMath.h b/Eigen/src/Core/arch/AltiVec/PacketMath.h
index b4546d6..96ca9d6 100644
--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
+++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
@@ -175,11 +175,6 @@
     HasExp = 1,
 #ifdef EIGEN_VECTORIZE_VSX
     HasSqrt = 1,
-#if !EIGEN_COMP_CLANG
-    HasRsqrt = 1,
-#else
-    HasRsqrt = 0,
-#endif
     HasTanh = EIGEN_FAST_MATH,
     HasErf = EIGEN_FAST_MATH,
     HasRint = 1,
@@ -220,11 +215,6 @@
     HasExp = 1,
 #ifdef EIGEN_VECTORIZE_VSX
     HasSqrt = 1,
-#if !EIGEN_COMP_CLANG
-    HasRsqrt = 1,
-#else
-    HasRsqrt = 0,
-#endif
     HasRint = 1,
 #else
     HasSqrt = 0,
@@ -2710,7 +2700,7 @@
     HasLog  = 0,
     HasExp  = 1,
     HasSqrt = 1,
-    HasRsqrt = 1,
+    HasRsqrt = 0,
     HasRound = 1,
     HasFloor = 1,
     HasCeil = 1,