x86/hibernate: Declare global functions in suspend.h

Three functions that are defined in x86 specific code to override
generic __weak implementations cause a warning because of a missing
prototype:

arch/x86/power/cpu.c:298:5: error: no previous prototype for 'hibernate_resume_nonboot_cpu_disable' [-Werror=missing-prototypes]
arch/x86/power/hibernate.c:129:5: error: no previous prototype for 'arch_hibernation_header_restore' [-Werror=missing-prototypes]
arch/x86/power/hibernate.c:91:5: error: no previous prototype for 'arch_hibernation_header_save' [-Werror=missing-prototypes]

Move the declarations into a global header so it can be included
by any file defining one of these.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/all/20230516193549.544673-14-arnd%40kernel.org

include/linux/suspend.h

@@ -452,6 +452,10 @@ extern struct pbe *restore_pblist;
 int pfn_is_nosave(unsigned long pfn);
 
 int hibernate_quiet_exec(int (*func)(void *data), void *data);
+int hibernate_resume_nonboot_cpu_disable(void);
+int arch_hibernation_header_save(void *addr, unsigned int max_size);
+int arch_hibernation_header_restore(void *addr);
+
 #else /* CONFIG_HIBERNATION */
 static inline void register_nosave_region(unsigned long b, unsigned long e) {}
 static inline int swsusp_page_is_forbidden(struct page *p) { return 0; }

kernel/power/power.h

@@ -26,9 +26,6 @@ extern void __init hibernate_image_size_init(void);
 /* Maximum size of architecture specific data in a hibernation header */
 #define MAX_ARCH_HEADER_SIZE	(sizeof(struct new_utsname) + 4)
 
-extern int arch_hibernation_header_save(void *addr, unsigned int max_size);
-extern int arch_hibernation_header_restore(void *addr);
-
 static inline int init_header_complete(struct swsusp_info *info)
 {
 	return arch_hibernation_header_save(info, MAX_ARCH_HEADER_SIZE);
@@ -41,8 +38,6 @@ static inline const char *check_image_kernel(struct swsusp_info *info)
 }
 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
 
-extern int hibernate_resume_nonboot_cpu_disable(void);
-
 /*
  * Keep some memory free so that I/O operations can succeed without paging
  * [Might this be more than 4 MB?]