Merge bitcoin/bitcoin#28352: test: Support powerpc64le in get_previous_releases.py

faf7e69 test: Support powerpc64le in get_previous_releases.py (MarcoFalke)

Pull request description:

  To test: `test/get_previous_releases.py -b -t /tmp/prev_releases v22.0`

  On master: `Not sure which binary to download for powerpc64le-unknown-linux-gnu`
  Here: (pass)

ACKs for top commit:
  fanquake:
    ACK faf7e69

Tree-SHA512: 33d9348f99e0d3924a6a5cba8833ec9e413e80167012b557922f3628069dabd555b02f98a6bfd0eb80e2bbbcdb50865b7bca216e1d080b1546ee4812abda4bc2

Author: fanquake

test/get_previous_releases.py

@@ -247,6 +247,7 @@ def check_host(args) -> int:
     if args.download_binary:
         platforms = {
             'aarch64-*-linux*': 'aarch64-linux-gnu',
+            'powerpc64le-*-linux-*': 'powerpc64le-linux-gnu',
             'riscv64-*-linux*': 'riscv64-linux-gnu',
             'x86_64-*-linux*': 'x86_64-linux-gnu',
             'x86_64-apple-darwin*': 'x86_64-apple-darwin',