Disable powerpc64 on stable

Author: brson

master/master.cfg

@@ -262,8 +262,6 @@ stable_cross_targets = [
   {'t': 'mipsel-unknown-linux-gnu', 'b': lincross},
   {'t': 'mipsel-unknown-linux-musl', 'b': lincross},
   {'t': 'powerpc-unknown-linux-gnu', 'b': lincross},
-  {'t': 'powerpc64-unknown-linux-gnu', 'b': lincross},
-  {'t': 'powerpc64le-unknown-linux-gnu', 'b': lincross},
   {'t': 'x86_64-apple-ios', 'b': ios},
   {'t': 'x86_64-rumprun-netbsd', 'b': lincross},
   {'t': 'x86_64-unknown-freebsd', 'b': xhost('freebsd'), 'host': True, 'pkg': True},