[POWERPC] MPIC MSI allocator

To support MSI on MPIC we need a way to reserve and allocate hardware irq
numbers, this patch implements an allocator for that purpose.

New firmware platforms must define a "msi-available-ranges" property on their
MPIC node for MSI to work. For U3/U4 we do a best-guess setup.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 33ecf89..fc0428a 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -36,6 +36,8 @@
 #include <asm/mpic.h>
 #include <asm/smp.h>
 
+#include "mpic.h"
+
 #ifdef DEBUG
 #define DBG(fmt...) printk(fmt)
 #else
@@ -891,6 +893,8 @@
 	if (hw >= mpic->irq_count)
 		return -EINVAL;
 
+	mpic_msi_reserve_hwirq(mpic, hw);
+
 	/* Default chip */
 	chip = &mpic->hc_irq;