platform/x86: acer-wmi: Add support for SW_TABLET_MODE on Switch devices

platform/x86: acer-wmi: Add support for SW_TABLET_MODE on Switch devices

Add support for SW_TABLET_MODE on the Acer Switch 10 (SW5-012) and the
acer Switch 10 (S1003) models.

There is no way to detect if this is supported, so this uses DMI based
quirks setting force_caps to ACER_CAP_KBD_DOCK (these devices have no
other acer-wmi based functionality).

The new SW_TABLET_MODE functionality can be tested on devices which
are not in the DMI table by passing acer_wmi.force_caps=0x40 on the
kernel commandline.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201019185628.264473-6-hdegoede@redhat.com