[SERIAL] CONFIG_PM=n slim: drivers/serial/8250_pci.c

Remove some code which is unneeded if CONFIG_PM=n.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>