m68knommu: remove legacy power managament from 68328 serial driver

Remove the legacy power management code from the 68328 serial driver.
It is not used, and there is no current kernel support for power
management on the 68328.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>