dts: fix DPDK git tarball cast bug

When running DTS with a git revision specified the following error occurs:
$ ./main.py --revision HEAD
[...]
FileNotFoundError: [Errno 2] No such file or directory:
     'dts/<framework.utils.DPDKGitTarball object at 0x78f69e73a5c0>'

Fix by casting DPDKGitTarball to Path, in order to stringify it correctly.

Bugzilla ID: 1496
Fixes: a23f224 ("dts: constrain DPDK source argument")

Signed-off-by: Alex Chapman <alex.chapman@arm.com>
Reviewed-by: Jack Bond-Preston <jack.bond-preston@arm.com>
Reviewed-by: Luca Vizzarro <luca.vizzarro@arm.com>
Reviewed-by: Paul Szczepanek <paul.szczepanek@arm.com>
Signed-off-by: 0-day Robot <robot@bytheb.org>

.mailmap

@@ -46,6 +46,7 @@ Aleksey Baulin <aleksey.baulin@gmail.com>
 Aleksey Katargin <gureedo@gmail.com>
 Ales Musil <amusil@redhat.com>
 Alessio Igor Bogani <alessio.bogani@elettra.eu>
+Alex Chapman <alex.chapman@arm.com>
 Alexander Bechikov <asb.tyum@gmail.com>
 Alexander Belyakov <abelyako@gmail.com>
 Alexander Chernavin <achernavin@netgate.com>

dts/framework/settings.py

@@ -415,7 +415,7 @@ def get_settings() -> Settings:
     args = parser.parse_args()
 
     if args.dpdk_revision_id:
-        args.dpdk_tarball_path = DPDKGitTarball(args.dpdk_revision_id, args.output_dir)
+        args.dpdk_tarball_path = Path(DPDKGitTarball(args.dpdk_revision_id, args.output_dir))
 
     args.test_suites = _process_test_suites(parser, args.test_suites)