arc: remove '__init' for setup_processor() and arc_init_IRQ()

They haven't '__init' in definition, but has '__init' in declaration.
And normal function start_kernel_secondary() may call setup_processor()
which will call arc_init_IRQ().

So need remove '__init' for both of them. The related warning (with
allmodconfig):

    MODPOST vmlinux.o
  WARNING: vmlinux.o(.text+0x3084): Section mismatch in reference from the function start_kernel_secondary() to the function .init.text:setup_processor()
  The function start_kernel_secondary() references
  the function __init setup_processor().
  This is often because start_kernel_secondary lacks a __init
  annotation or the annotation of setup_processor is wrong.
Signed-off-by: NChen Gang <gang.chen@asianux.com>

arch/arc/include/asm/irq.h

@@ -18,7 +18,7 @@
 
 #include <asm-generic/irq.h>
 
-extern void __init arc_init_IRQ(void);
+extern void arc_init_IRQ(void);
 extern int __init get_hw_config_num_irq(void);
 
 void arc_local_timer_setup(unsigned int cpu);

arch/arc/include/asm/setup.h

@@ -31,7 +31,7 @@ struct cpuinfo_data {
 extern int root_mountflags, end_mem;
 extern int running_on_hw;
 
-void __init setup_processor(void);
+void setup_processor(void);
 void __init setup_arch_memory(void);
 
 #endif /* __ASMARC_SETUP_H */