dmidecode.c: fix up the support of SMBIOS v2.8.0

dmidecode.c: Strip trailig zeroes from memory voltage values (DMI type 17).
dmidecode.c: Fix support for new processor upgrade types (DMI type 4) and new memory device type (DMI type 17.)

Signed-off-by: Anton Arapov <anton@redhat.com>