ath6kl: cleanup and move the ath6kl pm ops to be assigned statically

There should be no need to assign the pm ops dynamically, so
assign them statically and make them const. While we are
doing this just do some simple code style cleanup on the
routines and move them above prior to their assignment
into the driver ops.

This has no functional change other than assigning the
pm ops statically.

Cc: Naveen Singh <nsingh@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>