On x86/ACPI platforms touchscreens mostly just work without needing any
device/model specific configuration. But in some cases (mostly with Silead
and Goodix touchscreens) it is still necessary to manually specify various
touchscreen-properties on a per model basis.

touchscreen_dmi is a special place for DMI quirks for this, but it can be
challenging for users to figure out the right property values, especially
for Silead touchscreens where non of these can be read back from
the touchscreen-controller.

ATM users can only test touchscreen properties by editing touchscreen_dmi.c
and then building a completely new kernel which makes it unnecessary
difficult for users to test and submit properties when necessary for their
laptop / tablet model.

Add support for specifying properties on the kernel commandline to allow
users to easily figure out the right settings. See the added documentation
in kernel-parameters.txt for the commandline syntax.

Cc: Gregor Riepl <onitake@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240523143601.47555-1-hdegoede@redhat.com