ACPI: processor: idle: Rearrange declarations in header file

Group all of the declarations of functions that belong to the ACPI
processor idle driver together in one place in processor.h.

While at it, drop the unnecessary extern modifier from the declaraions
of two functions.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Link: https://patch.msgid.link/20250911112408.1668431-3-lihuisong@huawei.com
[ rjw: Subject and changelog rewrite ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: LiHuiSong1

include/acpi/processor.h

@@ -425,6 +425,8 @@ int acpi_processor_power_state_has_changed(struct acpi_processor *pr);
 int acpi_processor_hotplug(struct acpi_processor *pr);
 void acpi_processor_register_idle_driver(void);
 void acpi_processor_unregister_idle_driver(void);
+int acpi_processor_ffh_lpi_probe(unsigned int cpu);
+int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
 #endif /* CONFIG_ACPI_PROCESSOR_IDLE */
 
 /* in processor_thermal.c */
@@ -447,11 +449,6 @@ static inline void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
 }
 #endif	/* CONFIG_CPU_FREQ */
 
-#ifdef CONFIG_ACPI_PROCESSOR_IDLE
-extern int acpi_processor_ffh_lpi_probe(unsigned int cpu);
-extern int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi);
-#endif
-
 void acpi_processor_init_invariance_cppc(void);
 
 #endif