[ARM] 4222/1: S3C2443: Remove reference to missing S3C2443_PM

S3C2443_PM is not defined in our Kconfig, so
remove the reference from CPU_S3C2443 to stop
the configuration process warning about it.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>