Fix copy-paste error

Author: kleisauke

testcrate/build.rs

@@ -53,7 +53,7 @@ fn main() {
     if (target.arch == "aarch64" && target.os == "linux")
         || target.arch == "arm"
         || target.arch == "powerpc"
-        || target.arch == "powerpc64le"
+        || target.arch == "powerpc64"
         || target.arch == "powerpc64le"
         || target.arch == "i586"
         || target.os == "windows"