fb: Add new FBTYPE_EFIFB

Currently the type isn't set in the fbtype struct so any userland
program that call the FBIOGTYPE ioctl will think it's a FBTYPE_SUN1BW
which is far from the truth.
No app that I found find checks the type but at least now it's correct.

Reviewed by: emaste, tsoome
MFC after: 2 weeks
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D33221