ARM: fix some sparse errors in generic ARM code

arch/arm/kernel/return_address.c:37:6: warning: symbol 'return_address' was not declared. Should it be static?
arch/arm/kernel/setup.c:76:14: warning: symbol 'processor_id' was not declared. Should it be static?
arch/arm/kernel/traps.c:259:1: warning: symbol 'die_lock' was not declared. Should it be static?
arch/arm/vfp/vfpmodule.c:156:6: warning: symbol 'vfp_raise_sigfpe' was not declared. Should it be static?

Signed-off-by: Russell King <[e-mail]>

arch/arm/include/asm/cputype.h

···
 #define CPUID_EXT_ISAR4	"c2, 4"
 #define CPUID_EXT_ISAR5	"c2, 5"
 
+extern unsigned int processor_id;
+
 #ifdef CONFIG_CPU_CP15
 #define read_cpuid(reg)							\
 	({								\
···
 		__val;							\
 	})
 #else
-extern unsigned int processor_id;
 #define read_cpuid(reg) (processor_id)
 #define read_cpuid_ext(reg) 0
 #endif

arch/arm/kernel/return_address.c

···
  * the Free Software Foundation.
  */
 #include <linux/module.h>
+#include <linux/ftrace.h>
 
 #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
 #include <linux/sched.h>

arch/arm/kernel/traps.c

···
 	return ret;
 }
 
-DEFINE_SPINLOCK(die_lock);
+static DEFINE_SPINLOCK(die_lock);
 
 /*
  * This function is protected against re-entrancy.

arch/arm/vfp/vfpmodule.c

···
  * Raise a SIGFPE for the current process.
  * sicode describes the signal being raised.
  */
-void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs)
+static void vfp_raise_sigfpe(unsigned int sicode, struct pt_regs *regs)
 {
 	siginfo_t info;