KVM: arm64: Rationalise KVM banner output

We are not very consistent when it comes to displaying which mode
we're in (VHE, {n,h}VHE, protected or not). For example, booting
in protected mode with hVHE results in:

[    0.969545] kvm [1]: Protected nVHE mode initialized successfully

which is mildly amusing considering that the machine is VHE only.

We already cleaned this up a bit with commit 1f3ca70 ("KVM:
arm64: print Hyp mode"), but that's still unsatisfactory.

Unify the three strings into one and use a mess of conditional
statements to sort it out (yes, it's a slow day).

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240321173706.3280796-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: Marc Zyngier

arch/arm64/kvm/arm.c

@@ -2597,14 +2597,11 @@ static __init int kvm_arm_init(void)
 	if (err)
 		goto out_hyp;
 
-	if (is_protected_kvm_enabled()) {
-		kvm_info("Protected nVHE mode initialized successfully\n");
-	} else if (in_hyp_mode) {
-		kvm_info("VHE mode initialized successfully\n");
-	} else {
-		char mode = cpus_have_final_cap(ARM64_KVM_HVHE) ? 'h' : 'n';
-		kvm_info("Hyp mode (%cVHE) initialized successfully\n", mode);
-	}
+	kvm_info("%s%sVHE mode initialized successfully\n",
+		 in_hyp_mode ? "" : (is_protected_kvm_enabled() ?
+				     "Protected " : "Hyp "),
+		 in_hyp_mode ? "" : (cpus_have_final_cap(ARM64_KVM_HVHE) ?
+				     "h" : "n"));
 
 	/*
 	 * FIXME: Do something reasonable if kvm_init() fails after pKVM