microblaze: Remove NO_IRQ from architecture

NO_IRQ shouldn't be used by any driver. All Microblaze
drivers are fixed that's why NO_IRQ can be removed.

Also fix pci-common.c which has references to NO_IRQ removed.
Signed-off-by: Michal Simek <monstr@monstr.eu>
Reviewed-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/microblaze/include/asm/irq.h

@@ -27,8 +27,6 @@ typedef unsigned long irq_hw_number_t;
 
 extern unsigned int nr_irq;
 
-#define NO_IRQ 0
-
 struct pt_regs;
 extern void do_IRQ(struct pt_regs *regs);
 

arch/microblaze/pci/pci-common.c

@@ -242,7 +242,7 @@ int pci_read_irq_line(struct pci_dev *pci_dev)
 			 line, pin);
 
 		virq = irq_create_mapping(NULL, line);
-		if (virq != NO_IRQ)
+		if (virq)
 			irq_set_irq_type(virq, IRQ_TYPE_LEVEL_LOW);
 	} else {
 		pr_debug(" Got one, spec %d cells (0x%08x 0x%08x...) on %s\n",
@@ -253,7 +253,7 @@ int pci_read_irq_line(struct pci_dev *pci_dev)
 		virq = irq_create_of_mapping(oirq.controller, oirq.specifier,
 					     oirq.size);
 	}
-	if (virq == NO_IRQ) {
+	if (!virq) {
 		pr_debug(" Failed to map !\n");
 		return -1;
 	}