staging: ks7010: refactor LOCAL_EEPROM_SUM case in hostif_mib_get_confirm

This commit simplify conditional paths in LOCAL_EEPROM_SUM case
inside hostif_mib_get_confirm function. It change logic to handle
invalid values first and assign good ones at the end if it is the
case.

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