arc: use common of_flat_dt_match_machine

Convert arc to use the common of_flat_dt_match_machine function.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/kernel/setup.c

@@ -31,7 +31,7 @@
 int running_on_hw = 1;	/* vs. on ISS */
 
 char __initdata command_line[COMMAND_LINE_SIZE];
-struct machine_desc *machine_desc;
+const struct machine_desc *machine_desc;
 
 struct task_struct *_current_task[NR_CPUS];	/* For stack switching */