platform/x86: huawei-wmi: remove unnecessary member

platform/x86: huawei-wmi: remove unnecessary member

The `huawei_wmi::idev` array is not actually used by the driver,
so remove it. The piece of code that - I believe - was supposed
to fill the array is flawed, it did not actually set any of the
values inside the array. This was most likely masked by the fact
that the input devices are devm managed and that the only function
that needs a reference to the input devices is
`huawei_wmi_input_notify()`, however, that does not access the
appropriate input device via the `huawei_wmi` object.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Link: https://lore.kernel.org/r/20221005150032.173198-3-pobrn@protonmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>