Add more BCM gigabit PHYs

Gleaned from a public header file. 5402 and 5404 look like they may be
used on embedded devices. 5478 and 5488 are switch PHYs. 5754 change is just
to note a product alias.

Differential Revision: https://reviews.freebsd.org/D3338
Submitted by: kevin.bowling@kev009.com