chipset_enable.c: Mark Skylake U Premium as DEP

Tested reading, writing and erasing the internal flash chip using an
Acer Aspire ES1-572 laptop with an Intel i3-6006U. However, since all
ME-enabled chipsets are marked as DEP instead of OK, this one shall
follow suit as well.

Change-Id: Ib8ee9b5e811df74d2f48bd409806c72fe862bc24
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/39173


Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>