ARM: s3c: remove unused s3c2410_cpu_suspend() declaration

The s3c2410_cpu_suspend() has been removed since
commit 61b7f89 ("ARM: s3c: remove all s3c24xx support"), so
remove it.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20240813105545.1180788-3-cuigaosheng1@huawei.com
Fixes: 61b7f89 ("ARM: s3c: remove all s3c24xx support")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Author: gscui

arch/arm/mach-s3c/pm.h

@@ -48,8 +48,6 @@ extern unsigned long s3c_pm_flags;
 
 /* from sleep.S */
 
-extern int s3c2410_cpu_suspend(unsigned long);
-
 #ifdef CONFIG_PM_SLEEP
 extern int s3c_irq_wake(struct irq_data *data, unsigned int state);
 extern void s3c_cpu_resume(void);