Change asus_q500a_i8042_filter() into a generic i8042-filter,
using a new filter_i8042_e1_extended_codes flag in the quirks struct
to decide if e1 extended codes should be filtered out or not.

This is a preparation patch for adding support for filtering volume key
events being reported twice through both the PS/2 keyboard and asus-wmi.

Note while modifying the code also drop the unnecessary unlikely()
annotations, this is not in a hot path so those are not necessary.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20231120154235.610808-3-hdegoede@redhat.comReviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>