platform/x86: Add driver for Yoga Tablet Mode switch

This WMI driver for the tablet mode control switch for Lenovo Yoga
notebooks was originally written by Gergo Koteles. The mode is mapped to
a SW_TABLET_MODE switch capable input device.

Andrew followed the suggestions that were posted in reply to Gergo's RFC
patch, and on the v1 & v2 versions of this patch to follow-up and get it
merged.

Changes from Gergo's RFC:

 - Refactored obtaining a reference to the EC ACPI device needed for the
   quirk implementation as suggested by Hans de Goede
 - Applied small fixes and switched to always registering handles with
   the driver for automatic cleanup as suggested by Barnabás Pőcze.
 - Merged the lenovo_ymc_trigger_ec function with the
   ideapad_trigger_ymc_next_read function since it was no longer
   external.
 - Added the word "Tablet" to the driver description to hopefully make
   it more clear.
 - Fixed the LENOVO_YMC_QUERY_METHOD ID and the name string for the EC
   APCI device trigged for the quirk
 - Triggered the input event on probe so that the initial tablet mode
   state when the driver is loaded is reported to userspace as suggested
   by Armin Wolf.
 - Restricted the permissions of the ec_trigger parameter as suggested
   by Armin Wolf. Also updated the description.

We have tested this on the Yoga 7 14AIL7 for the non-quirk path and on
the Yoga 7 14ARB7 which has the firmware bug that requires triggering
the embedded controller to send the mode change events. This workaround
is also used by the Windows drivers.

According to reports at https://github.com/lukas-w/yoga-usage-mode,
which uses the same WMI devices, the following models should also work:
Yoga C940, Ideapad flex 14API, Yoga 9 14IAP7, Yoga 7 14ARB7, etc.

Signed-off-by: Gergo Koteles <[email protected]>
Co-developed-by: Andrew Kallmeyer <[email protected]>
Signed-off-by: Andrew Kallmeyer <[email protected]>
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]/
Tested-by: André Apitzsch <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>

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