Staging: slicoss: remove SLIC_POWER_MANAGEMENT_ENABLED

It was always disabled, so just remove it and the 2 lines of
code it was protecting.

Also remove SLIC_POWER_MANAGEMENT which was also disabled, yet
was never used.

Cc: Lior Dotan <liodot@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>