arm64: KVM: Add braces to multi-line if statement in virtual PMU code

The kernel is written in C, not python, so we need braces around
multi-line if statements. GCC 6 actually warns about this, thanks to the
fantastic new "-Wmisleading-indentation" flag:

 | virt/kvm/arm/pmu.c: In function ‘kvm_pmu_overflow_status’:
 | virt/kvm/arm/pmu.c:198:3: warning: statement is indented as if it were guarded by... [-Wmisleading-indentation]
 |    reg &= vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
 |    ^~~
 | arch/arm64/kvm/../../../virt/kvm/arm/pmu.c:196:2: note: ...this ‘if’ clause, but it is not
 |   if ((vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
 |   ^~

As it turns out, this particular case is harmless (we just do some &=
operations with 0), but worth fixing nonetheless.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>

virt/kvm/arm/pmu.c

@@ -193,11 +193,12 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
 {
 	u64 reg = 0;
 
-	if ((vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E))
+	if ((vcpu_sys_reg(vcpu, PMCR_EL0) & ARMV8_PMU_PMCR_E)) {
 		reg = vcpu_sys_reg(vcpu, PMOVSSET_EL0);
 		reg &= vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
 		reg &= vcpu_sys_reg(vcpu, PMINTENSET_EL1);
 		reg &= kvm_pmu_valid_counter_mask(vcpu);
+	}
 
 	return reg;
 }