SMBIOS: Correct length calculation for empty string table

If all strings in SMBIOS table are empty, smbios_string_table_len
function should return 2, cause every table must end with "\0\0".

Also replace "eos" field type in smbios structures
from char to u8.

Change-Id: Ia3178b0030aa71e1ff11a3fd3d102942f0027eb1
Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
Reviewed-on: https://review.coreboot.org/20840
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
3 files changed