genirq: define nr_irqs for architectures with GENERIC_HARDIRQS=n

Revert the sparse irq changes in m68k/s390/sparc and just define
nr_irqs as NR_IRQS for those architectures.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/m68k/kernel/ints.c

@@ -46,9 +46,6 @@
 #include <asm/q40ints.h>
 #endif
 
-int nr_irqs = NR_IRQS;
-EXPORT_SYMBOL(nr_irqs);
-
 extern u32 auto_irqhandler_fixup[];
 extern u32 user_irqhandler_fixup[];
 extern u16 user_irqvec_fixup[];

arch/s390/kernel/irq.c

@@ -17,9 +17,6 @@
 #include <linux/proc_fs.h>
 #include <linux/profile.h>
 
-int nr_irqs = NR_IRQS;
-EXPORT_SYMBOL(nr_irqs);
-
 /*
  * show_interrupts is needed by /proc/interrupts.
  */

arch/sparc/kernel/irq.c

@@ -55,10 +55,6 @@
 #define SMP_NOP2
 #define SMP_NOP3
 #endif /* SMP */
-
-int nr_irqs = NR_IRQS;
-EXPORT_SYMBOL(nr_irqs);
-
 unsigned long __raw_local_irq_save(void)
 {
 	unsigned long retval;

include/linux/interrupt.h

@@ -15,11 +15,13 @@
 #include <asm/ptrace.h>
 #include <asm/system.h>
 
-extern int nr_irqs;
-
 #ifndef CONFIG_GENERIC_HARDIRQS
-#define for_each_irq_desc(irq, desc)		\
+# define for_each_irq_desc(irq, desc)		\
 	for (irq = 0; irq < nr_irqs; irq++)
+
+# define nr_irqs		NR_IRQS
+#else
+extern int nr_irqs;
 #endif
 
 /*