staging: ks7010: refactor code for hostif_sme_sleep_set function

This commit refactors code for hostif_sme_sleep_set function. This
function was using a switch-case block to handle only two states
where the action to do for them is the same. Just refactor a bit
to check for return condition at first and doing the common action
after in other case.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>