hmt(4): Add support for touchpads with no "button type" or

"maximum number of contacts" usages.

Assume touchpad to be a clickpad if it has only internal button.
Set number of contacts to 5 for touchpads and to 10 for touchscreens.
Check for fetched report length to avoid reading of stalled data.
Fixes Dell Precision 7550 laptop.

Tested by: Shawn Webb <shawn.webb_AT_hardenedbsd_DOT_org>
PR: 257992
MFC after: 2 week