arm_gic: gic_update should always update all cores

This patch fixes so that gic_update always updates all the cores with
new pending irq states.  If the function returns early it is possible
to get interrupts that has already been acknowledged.
Signed-off-by: NJohan Karlsson <johan.karlsson@enea.com>
[PMM: rebased to apply to current master]
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/intc/arm_gic.c

@@ -71,7 +71,7 @@ void gic_update(GICState *s)
             || !(s->cpu_ctlr[cpu] & (GICC_CTLR_EN_GRP0 | GICC_CTLR_EN_GRP1))) {
             qemu_irq_lower(s->parent_irq[cpu]);
             qemu_irq_lower(s->parent_fiq[cpu]);
-            return;
+            continue;
         }
         best_prio = 0x100;
         best_irq = 1023;