smbios: enable setting processor family > 0xff

Many value of processor type exceed 0xff and have to be stored as u16
value. In the type 4 table set processor_family = 0xfe signaling that
field processor_family2 is used and write the actual value into the
processor_family2 field.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>