KVM: PPC: fix comparison to bool warning

Fix the following coccicheck warning:

./arch/powerpc/kvm/booke.c:503:6-16: WARNING: Comparison to bool
./arch/powerpc/kvm/booke.c:505:6-17: WARNING: Comparison to bool
./arch/powerpc/kvm/booke.c:507:6-16: WARNING: Comparison to bool

Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1604764178-8087-1-git-send-email-kaixuxia@tencent.com

arch/powerpc/kvm/booke.c

@@ -500,11 +500,11 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 
 		vcpu->arch.regs.nip = vcpu->arch.ivpr |
 					vcpu->arch.ivor[priority];
-		if (update_esr == true)
+		if (update_esr)
 			kvmppc_set_esr(vcpu, vcpu->arch.queued_esr);
-		if (update_dear == true)
+		if (update_dear)
 			kvmppc_set_dar(vcpu, vcpu->arch.queued_dear);
-		if (update_epr == true) {
+		if (update_epr) {
 			if (vcpu->arch.epr_flags & KVMPPC_EPR_USER)
 				kvm_make_request(KVM_REQ_EPR_EXIT, vcpu);
 			else if (vcpu->arch.epr_flags & KVMPPC_EPR_KERNEL) {