arm64: Fix duplicated Kconfig entries again

Commit 74397174

 attempted to clean up the power management options
for arm64, but when things were merged it didn't fully take effect.  Fix
it again.

Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>