ps/2 elantech: Enable v4 devices

Missing are v1, v2, and v3 devices that will
be enabled in separated commits.

This should help fixing the following tickets:
  #5179,  #5604,  #7755,  #9154,  #9173,
  #10059, #12669, #15340, #15729,
and perhaps many others.

Change-Id: I0cae0e1a61fc7f5a7304983170148681ebd8fe09
Reviewed-on: https://review.haiku-os.org/c/haiku/+/10015
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>

src/add-ons/kernel/bus_managers/ps2/ps2_elantech.cpp

@@ -977,7 +977,8 @@ probe_elantech(ps2_dev* dev)
 	}
 
 	// TODO: Update supported after testing all versions.
-	bool supported = !v4 || !v3 || !v2 || !v1;
+	// Only hardware version 4 devices are supported as of now, the other are untested.
+	bool supported = v4 || !v3 || !v2 || !v1;
 
 	if (supported && v3) {
 		uint8 samples[3];