arc: remove '__init' for first_lines_of_secondary()

first_lines_of_secondary() is a '__init' function, but it may be called
by __cpu_up() by _cpu_up() by cpu_up() which is a normal export symbol
function. So recommend to remove '__init'.

The related warning (with allmodconfig):

    MODPOST vmlinux.o
  WARNING: vmlinux.o(.text+0x315c): Section mismatch in reference from the function __cpu_up() to the function .init.text:first_lines_of_secondary()
  The function __cpu_up() references
  the function __init first_lines_of_secondary().
  This is often because __cpu_up lacks a __init
  annotation or the annotation of first_lines_of_secondary is wrong.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
diff --git a/arch/arc/include/asm/smp.h b/arch/arc/include/asm/smp.h
index c4fb211..eefc29f 100644
--- a/arch/arc/include/asm/smp.h
+++ b/arch/arc/include/asm/smp.h
@@ -30,7 +30,7 @@
  * APIs provided by arch SMP code to rest of arch code
  */
 extern void __init smp_init_cpus(void);
-extern void __init first_lines_of_secondary(void);
+extern void first_lines_of_secondary(void);
 extern const char *arc_platform_smp_cpuinfo(void);
 
 /*