staging: ks7010: refactor ks_wlan_set_mlme function

This commit refactors ks_wlan_set_mlme function changing
switch-case block for more simple if paths improving
readability.

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