tests: Assert that riscv64 is supported (MR 2476)

riscv64 is supported but currently not covered by the arch test suite.

Signed-off-by: Jens Reidel <adrian@travitia.xyz>

pmb/core/test_arch.py

@@ -27,6 +27,7 @@ def test_valid_arches():
     assert Arch.aarch64 in Arch.supported()
     assert Arch.armhf in Arch.supported()
     assert Arch.armv7 in Arch.supported()
+    assert Arch.riscv64 in Arch.supported()
 
     # kernel arch
     assert Arch.x86.kernel() == "x86"