um: Move declarations to proper headers

This will address below -Wmissing-prototypes warnings:

arch/um/kernel/initrd.c:18:12: warning: no previous prototype for ‘read_initrd’ [-Wmissing-prototypes]
arch/um/kernel/um_arch.c:408:19: warning: no previous prototype for ‘read_initrd’ [-Wmissing-prototypes]
arch/um/os-Linux/start_up.c:301:12: warning: no previous prototype for ‘parse_iomem’ [-Wmissing-prototypes]
arch/x86/um/ptrace_32.c:15:6: warning: no previous prototype for ‘arch_switch_to’ [-Wmissing-prototypes]
arch/x86/um/ptrace_32.c:101:5: warning: no previous prototype for ‘poke_user’ [-Wmissing-prototypes]
arch/x86/um/ptrace_32.c:153:5: warning: no previous prototype for ‘peek_user’ [-Wmissing-prototypes]
arch/x86/um/ptrace_64.c:111:5: warning: no previous prototype for ‘poke_user’ [-Wmissing-prototypes]
arch/x86/um/ptrace_64.c:171:5: warning: no previous prototype for ‘peek_user’ [-Wmissing-prototypes]
arch/x86/um/syscalls_64.c:48:6: warning: no previous prototype for ‘arch_switch_to’ [-Wmissing-prototypes]
arch/x86/um/tls_32.c:184:5: warning: no previous prototype for ‘arch_switch_tls’ [-Wmissing-prototypes]

Signed-off-by: Tiwei Bie <[e-mail]>
Signed-off-by: Richard Weinberger <[e-mail]>

arch/um/include/asm/ptrace-generic.h

···
 extern unsigned long getreg(struct task_struct *child, int regno);
 extern int putreg(struct task_struct *child, int regno, unsigned long value);
 
+extern int poke_user(struct task_struct *child, long addr, long data);
+extern int peek_user(struct task_struct *child, long addr, long data);
+
 extern int arch_set_tls(struct task_struct *new, unsigned long tls);
 extern void clear_flushed_tls(struct task_struct *task);
 extern int syscall_trace_enter(struct pt_regs *regs);

arch/um/include/shared/kern_util.h

···
 
 extern int start_uml(void);
 extern void paging_init(void);
+extern int parse_iomem(char *str, int *add);
 
 extern void uml_cleanup(void);
 extern void do_uml_exitcalls(void);

arch/um/kernel/physmem.c

···
 #include <as-layout.h>
 #include <init.h>
 #include <kern.h>
+#include <kern_util.h>
 #include <mem_user.h>
 #include <os.h>
 
···
 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 "	Example: mem=64M\n\n"
 );
-
-extern int __init parse_iomem(char *str, int *add);
 
 __uml_setup("iomem=", parse_iomem,
 "iomem=<name>,<file>\n"

arch/um/kernel/process.c

···
 		{ external_pid(), task });
 }
 
-extern void arch_switch_to(struct task_struct *to);
-
 struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to)
 {
 	to->thread.prev_sched = from;

arch/um/kernel/ptrace.c

···
 	user_disable_single_step(child);
 }
 
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
 long arch_ptrace(struct task_struct *child, long request,
 		 unsigned long addr, unsigned long data)
 {

arch/um/kernel/um_arch.h

···
 static inline void uml_dtb_init(void) { }
 #endif
 
+extern int __init read_initrd(void);
+
 #endif

arch/um/os-Linux/start_up.c

···
 #include <asm/unistd.h>
 #include <init.h>
 #include <os.h>
+#include <kern_util.h>
 #include <mem_user.h>
 #include <ptrace_user.h>
 #include <registers.h>

arch/x86/um/asm/ptrace.h

···
 extern int ptrace_set_thread_area(struct task_struct *child, int idx,
                                   struct user_desc __user *user_desc);
 
+extern int arch_switch_tls(struct task_struct *to);
+
 #else
 
 #define PT_REGS_R8(r) UPT_R8(&(r)->regs)
···
 		       unsigned long __user *addr);
 
 #endif
+
 #define user_stack_pointer(regs) PT_REGS_SP(regs)
+
+extern void arch_switch_to(struct task_struct *to);
+
 #endif /* __UM_X86_PTRACE_H */

arch/x86/um/ptrace_32.c

···
 #include <registers.h>
 #include <skas.h>
 
-extern int arch_switch_tls(struct task_struct *to);
-
 void arch_switch_to(struct task_struct *to)
 {
 	int err = arch_switch_tls(to);