kvm: x86: memset whole irq_eoi

gcc 7 warns:
arch/x86/kvm/ioapic.c: In function 'kvm_ioapic_reset':
arch/x86/kvm/ioapic.c:597:2: warning: 'memset' used with length equal to number of elements without multiplication by element size [-Wmemset-elt-size]

And it is right. Memset whole array using sizeof operator.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
[Added x86 subject tag]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/ioapic.c

@@ -594,7 +594,7 @@ static void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
 	ioapic->irr = 0;
 	ioapic->irr_delivered = 0;
 	ioapic->id = 0;
-	memset(ioapic->irq_eoi, 0x00, IOAPIC_NUM_PINS);
+	memset(ioapic->irq_eoi, 0x00, sizeof(ioapic->irq_eoi));
 	rtc_irq_eoi_tracking_reset(ioapic);
 }