x86, irq: Count legacy IRQs by legacy_pic->nr_legacy_irqs instead of NR_IRQS_LEGACY

Some platforms, such as Intel MID and mshypv, do not support legacy
interrupt controllers. So count legacy IRQs by legacy_pic->nr_legacy_irqs
instead of hard-coded NR_IRQS_LEGACY.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: xen-devel@lists.xenproject.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Tony Lindgren <tony@atomide.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Link: http://lkml.kernel.org/r/1402302011-23642-20-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 905956f..093f5f4 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -23,6 +23,7 @@
 #include <xen/features.h>
 #include <xen/events.h>
 #include <asm/xen/pci.h>
+#include <asm/i8259.h>
 
 static int xen_pcifront_enable_irq(struct pci_dev *dev)
 {
@@ -40,7 +41,7 @@
 	/* In PV DomU the Xen PCI backend puts the PIRQ in the interrupt line.*/
 	pirq = gsi;
 
-	if (gsi < NR_IRQS_LEGACY)
+	if (gsi < nr_legacy_irqs())
 		share = 0;
 
 	rc = xen_bind_pirq_gsi_to_irq(gsi, pirq, share, "pcifront");
@@ -511,7 +512,7 @@
 	xen_setup_acpi_sci();
 	__acpi_register_gsi = acpi_register_gsi_xen;
 	/* Pre-allocate legacy irqs */
-	for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
+	for (irq = 0; irq < nr_legacy_irqs(); irq++) {
 		int trigger, polarity;
 
 		if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
@@ -522,7 +523,7 @@
 			true /* Map GSI to PIRQ */);
 	}
 	if (0 == nr_ioapics) {
-		for (irq = 0; irq < NR_IRQS_LEGACY; irq++)
+		for (irq = 0; irq < nr_legacy_irqs(); irq++)
 			xen_bind_pirq_gsi_to_irq(irq, irq, 0, "xt-pic");
 	}
 	return 0;