mpr.4: Add Broadcom LSI 3808 to HARDWARE

The product brief "MegaRAID 9500 PCIe Gen 4.0 Tri-Mode Storage Adapters"
confirms that the LSI 3808 are supported in FreeBSD.

https://docs.broadcom.com/doc/MegaRAID-9500-Tri-Mode-Storage-Adapters

MFC after: 3 days (squashed with fixup commit)
Reviewed by: imp, ziaee
Differential Revision: https://reviews.freebsd.org/D52760

(cherry picked from commit 744c8d55445300074fc1906ad50aa6f394c1b8cf)
(cherry picked from commit 8caf467784ba9f502c52fb67d968e21b0ee5f9e0)