[PATCH] powerpc: Fix some MPIC + HT APIC buglets

Do disable, not enable, the HT APIC IRQ in the function that is
supposed to.
Enable the MPIC IRQ before enabling the downstream APIC IRQ, avoids
potentially losing an interrupt.
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/sysdev/mpic.c

@@ -234,7 +234,7 @@ static void mpic_shutdown_ht_interrupt(struct mpic *mpic, unsigned int source,
 	spin_lock_irqsave(&mpic->fixup_lock, flags);
 	writeb(0x10 + 2 * fixup->index, fixup->base + 2);
 	tmp = readl(fixup->base + 4);
-	tmp &= ~1U;
+	tmp |= 1;
 	writel(tmp, fixup->base + 4);
 	spin_unlock_irqrestore(&mpic->fixup_lock, flags);
 }
@@ -446,14 +446,15 @@ static unsigned int mpic_startup_irq(unsigned int irq)
 #ifdef CONFIG_MPIC_BROKEN_U3
 	struct mpic *mpic = mpic_from_irq(irq);
 	unsigned int src = irq - mpic->irq_offset;
+#endif /* CONFIG_MPIC_BROKEN_U3 */
+
+	mpic_enable_irq(irq);
 
+#ifdef CONFIG_MPIC_BROKEN_U3
 	if (mpic_is_ht_interrupt(mpic, src))
 		mpic_startup_ht_interrupt(mpic, src, irq_desc[irq].status);
-
 #endif /* CONFIG_MPIC_BROKEN_U3 */
 
-	mpic_enable_irq(irq);
-
 	return 0;
 }