ARM: S5PV210: Fix sysdev related warning messages

This patch fixes following warning messages when CONFIG_PM selected.

In file included from arch/arm/mach-s5pv210/mach-smdkv210.c:34:
arch/arm/plat-samsung/include/plat/pm.h:104: warning: 'struct sys_device'
declared inside parameter list
arch/arm/plat-samsung/include/plat/pm.h:104: warning: its scope is only this
definition or declaration, which is probably not what you want
arch/arm/plat-samsung/include/plat/pm.h:105: warning: 'struct sys_device'
declared inside parameter list

In file included from arch/arm/mach-s5pv210/mach-smdkc110.c:31:
arch/arm/plat-samsung/include/plat/pm.h:104: warning: 'struct sys_device'
declared inside parameter list
arch/arm/plat-samsung/include/plat/pm.h:104: warning: its scope is only this
definition or declaration, which is probably not what you want
arch/arm/plat-samsung/include/plat/pm.h:105: warning: 'struct sys_device'
declared inside parameter list

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>