powerpc/mpic: Remove MPIC_BROKEN_FRR_NIRQS and duplicate irq_count

The mpic->irq_count variable is only used as a software error-checking
limit to determine whether or not an IRQ number is valid.  In board code
which does not manually specify an IRQ count to mpic_alloc(), i.e. 0, it
is automatically detected from the number of ISUs and the ISU size.

In practice, all hardware ends up with irq_count == num_sources, so all
of the runtime checks on mpic->irq_count should just check the value of
mpic->num_sources instead.

When platform hardware does not correctly report the number of IRQs,
which only happens on the MPC85xx/MPC86xx, the MPIC_BROKEN_FRR_NIRQS
flag is used to override the detected value of num_sources with the
manual irq_count parameter.  Since there's no need to manually specify
the number of IRQs except in this case, the extra flag can be eliminated
and the test changed to "irq_count != 0".

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/mpic_msi.c b/arch/powerpc/sysdev/mpic_msi.c
index 0f67cd7..cfe3947 100644
--- a/arch/powerpc/sysdev/mpic_msi.c
+++ b/arch/powerpc/sysdev/mpic_msi.c
@@ -54,7 +54,7 @@
 	for (i = 100; i < 105; i++)
 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
 
-	for (i = 124; i < mpic->irq_count; i++)
+	for (i = 124; i < mpic->num_sources; i++)
 		msi_bitmap_reserve_hwirq(&mpic->msi_bitmap, i);
 
 
@@ -83,7 +83,7 @@
 {
 	int rc;
 
-	rc = msi_bitmap_alloc(&mpic->msi_bitmap, mpic->irq_count,
+	rc = msi_bitmap_alloc(&mpic->msi_bitmap, mpic->num_sources,
 			      mpic->irqhost->of_node);
 	if (rc)
 		return rc;