x86: fix mpparse/acpi interaction

Sitsofe Wheeler reported boot problems on linux-next.

It looks like the same issue as found by Soeren Sandman in 7575217f656a93,
"x86: initialize all fields of mp_irqs[mp_irq_entries]".

But his fix is also not complete, as dstapic is used before it assigned.
Reported-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Bisected-by: NSitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: NAlexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/acpi/boot.c

@@ -1019,6 +1019,11 @@ void __init mp_config_acpi_legacy_irqs(void)
 	for (i = 0; i < 16; i++) {
 		int idx;
 
+		mp_irqs[mp_irq_entries].mp_type = MP_INTSRC;
+		mp_irqs[mp_irq_entries].mp_irqflag = 0;	/* Conforming */
+		mp_irqs[mp_irq_entries].mp_srcbus = MP_ISA_BUS;
+		mp_irqs[mp_irq_entries].mp_dstapic = mp_ioapics[ioapic].mp_apicid;
+
 		for (idx = 0; idx < mp_irq_entries; idx++) {
 			struct mp_config_intsrc *irq = mp_irqs + idx;
 
@@ -1039,10 +1044,6 @@ void __init mp_config_acpi_legacy_irqs(void)
 			continue;	/* IRQ already used */
 		}
 
-		mp_irqs[mp_irq_entries].mp_type = MP_INTSRC;
-		mp_irqs[mp_irq_entries].mp_irqflag = 0;	/* Conforming */
-		mp_irqs[mp_irq_entries].mp_srcbus = MP_ISA_BUS;
-		mp_irqs[mp_irq_entries].mp_dstapic = mp_ioapics[ioapic].mp_apicid;
 		mp_irqs[mp_irq_entries].mp_irqtype = mp_INT;
 		mp_irqs[mp_irq_entries].mp_srcbusirq = i;	/* Identity mapped */
 		mp_irqs[mp_irq_entries].mp_dstirq = i;