[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/include/asm-powerpc/mpic.h b/include/asm-powerpc/mpic.h
index 22c85c4..2ffb06a 100644
--- a/include/asm-powerpc/mpic.h
+++ b/include/asm-powerpc/mpic.h
@@ -301,6 +301,11 @@
 	u32			*hw_set;
 #endif
 
+#ifdef CONFIG_PCI_MSI
+	spinlock_t		bitmap_lock;
+	unsigned long		*hwirq_bitmap;
+#endif
+
 	/* link */
 	struct mpic		*next;