Fix preverse for PowerPC.

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 a4b134c..6a2f0e6 100644
--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
+++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
@@ -94,9 +94,7 @@
 
 static Packet16uc p16uc_REVERSE32 = {12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3};
 static Packet16uc p16uc_REVERSE16 = {14, 15, 12, 13, 10, 11, 8, 9, 6, 7, 4, 5, 2, 3, 0, 1};
-#ifndef _ARCH_PWR9
 static Packet16uc p16uc_REVERSE8 = {15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
-#endif
 
 #ifdef _BIG_ENDIAN
 static Packet16uc p16uc_DUPLICATE32_HI = {0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 6, 7, 4, 5, 6, 7};
@@ -1928,19 +1926,11 @@
 }
 template <>
 EIGEN_STRONG_INLINE Packet16c preverse(const Packet16c& a) {
-#ifdef _ARCH_PWR9
-  return vec_revb(a);
-#else
   return vec_perm(a, a, p16uc_REVERSE8);
-#endif
 }
 template <>
 EIGEN_STRONG_INLINE Packet16uc preverse(const Packet16uc& a) {
-#ifdef _ARCH_PWR9
-  return vec_revb(a);
-#else
   return vec_perm(a, a, p16uc_REVERSE8);
-#endif
 }
 template <>
 EIGEN_STRONG_INLINE Packet8bf preverse(const Packet8bf& a) {