hwmon: (asus_atk0110) Do not fail if MBIF is missing

MBIF (motherboard identification) is only used to print the name of
the board, it's not essential for the driver; do not fail if it's
missing. Based on Juan's patch.

Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Acked-by: Juan RP <xtraeme@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>