staging: ks7010: clean SME_MIC_FAILURE_REQUEST case in hostif_sme_execute

This commit cleans code for the event SME_MIC_FAILURE_REQUEST
changing if logic to handle invalid value first and using a
local variable.

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