Revert "Input: elantech - enable SMBus on new (2018+) systems"

Revert "Input: elantech - enable SMBus on new (2018+) systems"

This reverts commit b28c1412b07adeff0a335b68df6df00cfd0e5890.

Apparently use dmi_get_bios_year() as manufacturing date isn't accurate
and this breaks older laptops with new BIOS update.

So let's revert this patch.

There are still new HP laptops still need to use SMBus to support all
features, but it'll be enabled via a whitelist.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191001070845.9720-1-kai.heng.feng@canonical.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>