sparc32, leon: bugfix in LEON SMP interrupt init

During converting per-cpu ticker to genirq layer some
IRQ initialization code was removed by commit
2cf9530420e446bb61f665d02afeb81070106900 ("sparc32,leon:
per-cpu ticker use genirq per-cpu handler").

This patch reintroduces the code at the same place it was
removed from. IRQ12 - IRQ14 will crash on LEON SMP without
this patch because it will run the SUN4M IRQ trap handler.

Reported-by: Jan Andersson <jan@gaisler.com>
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/leon_kernel.c

@@ -376,6 +376,22 @@ void __init leon_init_timers(irq_handler_t counter_fn)
 		prom_halt();
 	}
 
+#ifdef CONFIG_SMP
+	{
+		unsigned long flags;
+
+		/*
+		 * In SMP, sun4m adds a IPI handler to IRQ trap handler that
+		 * LEON never must take, sun4d and LEON overwrites the branch
+		 * with a NOP.
+		 */
+		local_irq_save(flags);
+		patchme_maybe_smp_msg[0] = 0x01000000; /* NOP out the branch */
+		local_flush_cache_all();
+		local_irq_restore(flags);
+	}
+#endif
+
 	LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
 			      LEON3_GPTIMER_EN |
 			      LEON3_GPTIMER_RL |