sh: Kill off machvec IRQ hinting.

Everything is using sparseirq these days, so we have no need to
arbitrarily size nr_irqs ahead of time. The legacy IRQ pre-allocation
likewise has no meaning for us, so that's killed off too. We now depend
on nr_irqs expansion by the generic hardirq layer instead.

It's also worth noting that the majority of boards had completely bogus
values for their nr_irqs relative to their CPU and configurations, so
this ends up correcting behaviour for quite a few platforms.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/irq.h b/arch/sh/include/asm/irq.h
index 2a62017..0e4f532 100644
--- a/arch/sh/include/asm/irq.h
+++ b/arch/sh/include/asm/irq.h
@@ -5,12 +5,15 @@
 #include <asm/machvec.h>
 
 /*
- * A sane default based on a reasonable vector table size, platforms are
- * advised to cap this at the hard limit that they're interested in
- * through the machvec.
+ * Only legacy non-sparseirq platforms have to set a reasonably sane
+ * value here. sparseirq platforms allocate their irq_descs on the fly,
+ * so will expand automatically based on the number of registered IRQs.
  */
-#define NR_IRQS			512
-#define NR_IRQS_LEGACY		8	/* Legacy external IRQ0-7 */
+#ifdef CONFIG_SPARSE_IRQ
+# define NR_IRQS		8
+#else
+# define NR_IRQS		512
+#endif
 
 /*
  * This is a special IRQ number for indicating that no IRQ has been