On some Panasonic models the volume up/down/mute keypresses get
reported both through the Panasonic ACPI HKEY interface as well as
through the atkbd device.

Filter out the atkbd scan-codes for these to avoid reporting presses
twice.

Note normally we would leave the filtering of these to userspace by mapping
the scan-codes to KEY_UNKNOWN through /lib/udev/hwdb.d/60-keyboard.hwdb.
However in this case that would cause regressions since we were filtering
the Panasonic ACPI HKEY events before, so filter these in the kernel.

Fixes: ed83c917 ("platform/x86: panasonic-laptop: Resolve hotkey double trigger bug")
Reported-and-tested-by: Stefan Seyfried <seife+kernel@b1-systems.com>
Reported-and-tested-by: Kenneth Chan <kenneth.t.chan@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220624112340.10130-7-hdegoede@redhat.com