fix smbios blob length overflow

fix smbios blob length overflow

When tables are more than 64K, size of copied tables will be
truncated due to cast from u32 to u16, and as result only
a small portion of the tables will be copied in the end.
That leads to corrupted tables (a part from QEMU and
remainder is whatever was in memory block allocated for
the tables).

Fix it by making qtables_len 32bit int.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>