platform/x86: acer-wmi: Ignore backlight event

platform/x86: acer-wmi: Ignore backlight event

On the Acer Nitro AN515-58, the event 4 - 0 is send by the ACPI
firmware when the backlight up/down keys are pressed. Ignore this
event to avoid spamming the kernel log with error messages, as the
acpi-video driver already handles brightness up/down events.

Reported-by: Bugaddr <Bugaddr@protonmail.com>
Closes: https://bugaddr.tech/posts/2025-11-16-debugging-the-acer-nitro-5-an515-58-fn-f10-keyboard-backlight-bug-on-linux/#wmi-interface-issues
Tested-by: Bugaddr <Bugaddr@protonmail.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20251117155938.3030-1-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>