uchcom.4: Add HARDWARE, makeover

Tag spdx, improve document description for apropos, improve synopsis
for clarity and consistency, improve description to explain usage,
improve hardware for hardware release notes, mention the sysctl, xref
the application to use this driver, improve history.

MFC: no (unless change adding CH9102/CH343 mfcs)
Fixes: 1395712cab8e9 (add support for CH9102 and CH343)
Reviewed by: carlavilla, kevlo
Differential Revision: https://reviews.freebsd.org/D51036