selftests/powerpc: Add test for VPHN

The goal is to verify vphn_unpack_associativity() parses VPHN numbers
correctly. We feed it with a variety of input values and compare with
expected results.

PAPR+ does not say much about VPHN parsing: I came up with a list of
tests that check many simple cases and some corner ones. I wouldn't
dare to say the list is exhaustive though.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
[mpe: Rework harness logic, rename to test-vphn, add -m64]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

tools/testing/selftests/powerpc/vphn/Makefile

@@ -0,0 +1,15 @@
+PROG := test-vphn
+
+CFLAGS += -m64
+
+all: $(PROG)
+
+$(PROG): ../harness.c
+
+run_tests: all
+	./$(PROG)
+
+clean:
+	rm -f $(PROG)
+
+.PHONY: all run_tests clean