kvm: x86: remove unused but set variable

The local variable *gpa_offset* is set but not used afterwards,
which make the compiler issue a warning with option
-Wunused-but-set-variable. Remove it to avoid the warning.
Signed-off-by: NJiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -2162,7 +2162,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	case MSR_KVM_SYSTEM_TIME_NEW:
 	case MSR_KVM_SYSTEM_TIME: {
-		u64 gpa_offset;
 		struct kvm_arch *ka = &vcpu->kvm->arch;
 
 		kvmclock_reset(vcpu);
@@ -2184,8 +2183,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (!(data & 1))
 			break;
 
-		gpa_offset = data & ~(PAGE_MASK | 1);
-
 		if (kvm_gfn_to_hva_cache_init(vcpu->kvm,
 		     &vcpu->arch.pv_time, data & ~1ULL,
 		     sizeof(struct pvclock_vcpu_time_info)))