firmware: dmi: Stop decoding on broken entry

If a DMI table entry is shorter than 4 bytes, it is invalid. Due to
how DMI table parsing works, it is impossible to safely recover from
such an error, so we have to stop decoding the table.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Link: https://lore.kernel.org/linux-kernel/Zh2K3-HLXOesT_vZ@liuwe-devbox-debian-v2/T/


Reviewed-by: Michael Kelley <mhklinux@outlook.com>