Remove the ancient PPC64 hack

The package should honor the global build flags

xz.spec

@@ -4,7 +4,7 @@
 Summary:	LZMA compression utilities
 Name:		xz
 Version:	5.2.5
-Release:	5%{?dist}
+Release:	6%{?dist}
 
 # Scripts xz{grep,diff,less,more} and symlinks (copied from gzip) are
 # GPLv2+, binaries are Public Domain (linked against LGPL getopt_long but its
@@ -89,10 +89,6 @@ commands that deal with the older LZMA format.
 %build
 export CFLAGS="%optflags"
 
-%ifarch %{power64}
-  CFLAGS="$CFLAGS -O3"
-%endif
-
 %ifarch %ix86
   # rhbz#1630650, annocheck reports the following message because liblzma uses
   # crc*_x86.S asm code on i686:
@@ -160,6 +156,9 @@ LD_LIBRARY_PATH=$PWD/src/liblzma/.libs make check
 
 
 %changelog
+* Fri Feb 12 2021 Michal Schorm <mschorm@redhat.com> - 5.2.5-6
+- Remove the ancient PPC64 hack
+
 * Thu Jan 28 2021 Fedora Release Engineering <releng@fedoraproject.org> - 5.2.5-5
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild