ARM: S3C24XX: avoid a Kconfig warning

The PM_H1940 symbol is used by two platforms: RX3715 and RX1950. However,
it is hidden inside of the the CPU_S3C2410 conditional, which is only
set by one of them, so we get a lot of randconfig warnings like

warning: (MACH_RX3715 && MACH_RX1950) selects PM_H1940 which has unmet direct dependencies (ARCH_S3C24XX && CPU_S3C2410)

This moves it outside of the conditional to remove the warnings.

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