platform/x86: touchscreen_dmi: Drop "silead,max-fingers" property

The silead touchscreen driver now defaults to 10 fingers, so it is no
longer necessary to have a "silead,max-fingers=10" property for each
silead touchscreen model. Drop this property from all the configs.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240525193854.39130-3-hdegoede@redhat.com