ARM: S3C24XX: fix header file inclusions

The pm-core.h file does not include all the necessary headers,
and has a static declaration for a function that is not
defined in the same file, causing SAMSUNG_PM_DEBUG to
break on s3c24xx:

arch/arm/mach-s3c24xx/include/mach/pm-core.h:50:91: warning: 's3c_pm_show_resume_irqs' used but never defined
arch/arm/mach-s3c24xx/include/mach/pm-core.h: In function 's3c_pm_debug_init_uart':
arch/arm/mach-s3c24xx/include/mach/pm-core.h:16:34: error: 'S3C2410_CLKCON' undeclared (first use in this function)
  unsigned long tmp = __raw_readl(S3C2410_CLKCON);
                                  ^

This moves the code around slightly to avoid the errors.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene@kernel.org>