ARM: dts: sun8i: Make et-q8-v1.6.dts a symlink to q8-tablet.dts

ARM: dts: sun8i: Make et-q8-v1.6.dts a symlink to q8-tablet.dts

A33 Q8 tablets with the et-q8-v1.6 pcb will work fine with the
generic q8-tablet.dts and given the many variants of PCBs found in
Q8 tablets using such a specific dts name was a mistake in hindsight.

We cannot just drop the et-q8-v1.6.dtb as existing u-boot configs
may very well point to it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>