Disable ppc test

Author: calebzulawski

.github/workflows/ci.yml

@@ -194,7 +194,8 @@ jobs:
           - mips-unknown-linux-gnu
           - mips64-unknown-linux-gnuabi64
           - riscv64gc-unknown-linux-gnu
-          - powerpc-unknown-linux-gnu
+          # TODO this test works, but it appears to time out
+          # - powerpc-unknown-linux-gnu
           # TODO this test is broken, but it appears to be a problem with QEMU, not us.
           # - powerpc64le-unknown-linux-gnu
           # TODO enable this once a new version of cross is released