arm64: ssbs: Don't treat CPUs with SSBS as unaffected by SSB

SSBS provides a relatively cheap mitigation for SSB, but it is still a
mitigation and its presence does not indicate that the CPU is unaffected
by the vulnerability.

Tweak the mitigation logic so that we report the correct string in sysfs.

Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/cpu_errata.c

@@ -386,15 +386,17 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
 
 	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
 
-	if (this_cpu_has_cap(ARM64_SSBS)) {
-		required = false;
-		goto out_printmsg;
-	}
-
 	/* delay setting __ssb_safe until we get a firmware response */
 	if (is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list))
 		this_cpu_safe = true;
 
+	if (this_cpu_has_cap(ARM64_SSBS)) {
+		if (!this_cpu_safe)
+			__ssb_safe = false;
+		required = false;
+		goto out_printmsg;
+	}
+
 	if (psci_ops.smccc_version == SMCCC_VERSION_1_0) {
 		ssbd_state = ARM64_SSBD_UNKNOWN;
 		if (!this_cpu_safe)