arc: remove '__init' for get_hw_config_num_irq()

get_hw_config_num_irq() may be called by normal iss_model_init_smp()
which is a function pointer for 'init_smp' which may be called by
first_lines_of_secondary() which also need be normal too.

The related warning (with allmodconfig):

    MODPOST vmlinux.o
  WARNING: vmlinux.o(.text+0x5814): Section mismatch in reference from the function iss_model_init_smp() to the function .init.text:get_hw_config_num_irq()
  The function iss_model_init_smp() references
  the function __init get_hw_config_num_irq().
  This is often because iss_model_init_smp lacks a __init
  annotation or the annotation of get_hw_config_num_irq is wrong.
Signed-off-by: Chen Gang <gang.chen@asianux.com>

arch/arc/include/asm/irq.h

@@ -19,7 +19,7 @@
 #include <asm-generic/irq.h>
 
 extern void arc_init_IRQ(void);
-extern int __init get_hw_config_num_irq(void);
+extern int get_hw_config_num_irq(void);
 
 void arc_local_timer_setup(unsigned int cpu);
 

arch/arc/kernel/irq.c

@@ -150,7 +150,7 @@ void arch_do_IRQ(unsigned int irq, struct pt_regs *regs)
 	set_irq_regs(old_regs);
 }
 
-int __init get_hw_config_num_irq(void)
+int get_hw_config_num_irq(void)
 {
 	uint32_t val = read_aux_reg(ARC_REG_VECBASE_BCR);