kselftest/arm64: Fix test for streaming FPSIMD write in sve-ptrace

Since f916dd3 ("arm64/fpsimd: ptrace: Mandate SVE payload for
streaming-mode state") we do not support writing FPSIMD payload data when
writing NT_ARM_SSVE but the sve-ptrace test has an explicit test for
this being supported which was not updated to reflect the new behaviour.
Fix the test to expect a failure when writing FPSIMD data to the
streaming mode register set.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250609-kselftest-arm64-ssve-fixups-v2-2-998fcfa6f240@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: broonie

tools/testing/selftests/arm64/fp/sve-ptrace.c

@@ -301,8 +301,10 @@ static void ptrace_sve_fpsimd(pid_t child, const struct vec_type *type)
 			p[j] = j;
 	}
 
+	/* This should only succeed for SVE */
 	ret = set_sve(child, type, sve);
-	ksft_test_result(ret == 0, "%s FPSIMD set via SVE: %d\n",
+	ksft_test_result((type->regset == NT_ARM_SVE) == (ret == 0),
+			 "%s FPSIMD set via SVE: %d\n",
 			 type->name, ret);
 	if (ret)
 		goto out;