ufshci.4: Move hardware to HARDWARE

This lets us pull them automatically into the hardware release notes.

Note the beautiful introductory sentence here, this pattern can maybe
improve the relationship between DESCRIPTION introductory sentence and
HARDWARE.

MFC: never (ufshci does not mfc)
Reviewed by: 0mp, christos, imp
Differential Revision: https://reviews.freebsd.org/D51379